PHYSICS PRACTICAL NOTE BOOK€¦ · ohm Mean Resistance in ohm r 1 only 1. 2. 3. r 2 only 1. 2. 3. r 1 and r 2 in parallel 1. 2. 3. CALCULATIONS • Calculation for verification of

Prepared by Mita Chourasia, PGT Physics, KV1 Bhopal

PHYSICS PRACTICAL

NOTE BOOK

SESSION:………………………………………………

NAME OF STUDENT:………………………………..

ROLL NO:……………………………………………..

CLASS &SEC: 12th

…………………\


INDEX PAGE

S.

No.

Date Name of the Experement Page

No.

Signature

of Teacher


S.

No.


No.

Signature

of Teacher


INDEX PAGE

ACTIVITIES

S.

No.


No.

Signature

of Teacher


EXPERIMENT NO. ………………………. DATE:……………

VERIFICATION OF OHM’S LAW

AIM

To establish the relation between current and potential difference across for a metallic

wire and to find resistance per cm of the wire:

MATERIAL REQUIRED

A voltmeter and an ammeter of suitable range, a resistance wire of 1 m long, a battery

eliminator, a rheostat a one way key and connecting wires.

THEORY

• Ohm’s law states that the current flowing through a conductor is directly

proportional to the potential difference across its ends, provided the temperature

remains constant.

• That is V α I or V = IR, where R is the resistance of the material of the conductor

and depends on dimensions of the conductor.

CIRCUIT DIAGRAM

MODEL GRAPH


PROCEDURE

1. Draw the circuit diagram as shown above. Arrange the apparatus as per the circuit

diagram. Clean the ends of the connecting wires with sand paper and make them

shiny.

2. Make the connections as per circuit diagram. All connections must be neat and tight. Take care to connect the ammeter and voltmeter with their correct polarity. (+ve to +ve and -ve to -ve).

3. Determine the zero error and least count of the ammeter and voltmeter and record them. Adjust the rheostat to pass a low current.

4. Insert the key K and slide the rheostat contact to see whether the ammeter and voltmeter are showing deflections properly. Adjust the rheostat to get a small deflection in ammeter and voltmeter.

5. Record the readings of the ammeter and voltmeter. Take at least six sets of readings by adjusting the rheostat gradually. Plot a graph with V along x-axis and I along y-axis. The graph will be a straight line, which verifies Ohm's law.

6. Determine the slope of the V-I graph. The reciprocal of the slope gives resistance of the wire

OBSERVATIONS

• Range of the given ammeter = __________ A

• Least count of the given ammeter = __________A

• Range of the given voltmeter __________= V

• Least count of the given voltmeter = __________V

• Mean value of V/I from observations, R = __________ohm

• Length of the wire l = __________cm

OBSERVATION TABLE

S.No. Voltmeter Reading (V) Ammeter Reading (mA) Resistance = V/I (Ω)


From graph

• Slope of I vs V graph =__________

• R from graph = 1/ slope =__________ ohm

CALCULATIONS

•The mean value of resistance of the given wire R =

RESULTS

1. The V- I graph for a metallic conductors is a straight line passing through origin.

2. The resistance per cm is ohm - cm

PRECAUTIONS

1. Always connect the ammeter in series and voltmeter in parallel with the circuit.

2. Insert the key only when taking observations.

3. A low resistance rheostat should be used specific.

The resistance per cm of the wire = Ωcm

• •

•

•


EXPERIMENT No……………………… DATE:………………

METER BRIDGE-RESISTANCE OF WIRE

AIM

To find the resistance of a given wire using a meter bridge and hence determine the

specific resistance of its materials.

MATERIALS REQUIRED

Meter bridge (slide wire bridge), leclanche cell or battery eliminator, galvanometer,

resistance box, jockey, one way key, resistance wire, screw gauge, meter scale,

connecting wires

THEORY

Wheatstone’s principle

• The meter bridge operates under Wheatstone’s principle. Here, four resistors P,

Q, R, and S are connected to form the network ABCD.

• The terminals A and C are connected to a battery, and the terminals C and D

are connected to a galvanometer through keys K1 and K2 respectively.

• In the balancing condition, there is no deflection on the galvanometer. Then,

P/Q = R/S

CIRCUIT DIAGRAM


PROCEDURE

1. Arrange the required materials on a table and make the connections as per the

connections diagram.

2. Connect the resistance wire in the left gap (between c & d) and resistance box in

the right gap.

3. Introduce some resistance in the circuit by taking out some resistance from the

resistance box.

4. Plug the key. Bring the jockey in contact with the end A first, and then with C.

Note the deflection on the galvanometer.

5. If the galvanometer deflects in the opposite direction, the connections are right

and the null point is in between A and C. If the galvanometer deflected towards

a single side, then check the connection.

6. Now, slide the jockey slowly over the wire starting from one and (say, A) and

note the galvanometer deflection. Continue the process till the balancing point is

reached.

7. Balancing point is the point at which the galvanometer shows zero deflection.

Now, note the position of the jockey from end A. Take it as the balancing length

(l) using the metre scale.

8. Repeat the process for different values of R. The balancing length is measured

each time.

9. Now, interchange the position of resistance wire and resistance box in gaps AB

and CD.

10. Repeat the above steps to find the balancing length, for the same values of R..

We can calculate the unknown resistance of the resistance wire by using the

relation.

11. resistance Measure the diameter of the given resistance wire using a screw gauge.

Hence, its radius(r) can be found.

12. Also measure the length (L) of the wire using a metre scale.

13. From the measured values, the specific resistance (resistivity) of the given wire can

be calculated using the relation,


OBSERVATIONS

a. To find resistance of the given wire

S.No. Resistance in ohm Balancing

length AB= l

cm

Length BC=

(100-l) cm

Unknown

Resistance

X=R

)(

)100(

ohm

l

l

b. To find diameter of the wire

•Least count of the screw gauge = __________mm

•Zero correction of the screw gauge = __________ mm

S.No. LSR (mm) CSD CSR =

(CSD x LC)

Diameter

TR=(LSR+CSR)

(mm)

Mean Diameter

(mm)

CALCULATIONS

• Diameter of the wire, d =______________cm

• Length of the wire, L = ______________cm

• Resistance of the wire, X = ______________Ω

Resistivity (specific resistance) of the wire =X. L

D

4

2=_________ Ωcm

= _____________ Ωm

RESULT

• The unknown resistance of the given resistance wire, X =_________ Ω

• The specific resistance (resistivity) of the given resistance wire, ρ = ________ Ω m


PRECAUTIONS

1. All the connections and plugs should be tight.

2. Jockey should be moved gently over the meter bridge wire.

3. Null point should be brought nearly in the mid part of the wire say between

45cm to 55cm


EXPERIMENT……….. DATE:…………….

METER BRIDGE- SERIES COMBINATION OF RESISTANCES

AIM

To verify the laws of combination (series) of resistances using a meter bridge.

MATERIALS REQUIRED

Metre bridge (slide wire bridge), Leclanche cell or Battery eliminator, Galvanometer,

Resistance box , Jockey , One way key. A resistance wire, Screw gauge, Metre scale,

Connecting wires

THEORY

Resistors in Series

When two or more resistors are connected such a way that one end of one resistor is

connected to the starting end of the other, then the circuit is called a Series Circuit.

When the two resistors X1 and X2 are connected in series in a circuit, the current I

passing through each resistor is same.

Thus, when a number of resistors are connected in series, the effective resistance is

equal to the sum of the individual resistances. This is called the law of combination

of resistances in series. Adding resistors in series always increases the effective

resistance.

CIRCUIT DIAGRAM


PROCEDURE

1. Mark the two resistance coils as r1 and r2.

2. To find r1 and r2 seperately.

3. Connect the two coils r1 and r2 in series as shown in figure in the right gap of

meter bridge and find the resistance of this combination. Take at least three

sets of observations.

4. Record your observations as follows.

OBSERVATIONS

Table for length (l) and unknown resistance(X)

Resist

ance

coil

S.

No.

Resistanc

e from the

resistance

box R

ohm

Length

AD = l cm

Length

DC =

(100 - l)

cm

Resistance

xRl

lr

100

ohm

Mean

Resistance

in ohm

r1 only 1.

2.

3.

r2 only 1.

2.

3.

r1 and

r2 in

series

1.

2.

3.


CALCULATIONS

• Calculations for r1 only, r2 only and r1 and r2 in series.

• Calculation for verification of law

• Experimental value Rs

• Theoritical value r1 + r2 =

• Difference if any

RESULT

Within limits of experimental error, theoretical and experimental values are R s are

same. Hence law of resistance in series is verified.

PRECAUTIONS

1. The connections should be neat and clean.

2. Thick copper wires should be used for connections after removing the

insulations near their ends by rubbing with sand paper.

3. Move the jockey gently over the bridge wire and do not rub it.


EXPERIMENT………………….. DATE:………….

METER BRIDGE- PARALLEL COMBINATION OF RESISTANCES

AIM

To verify the laws of combination (parallel) of resistances using a meter bridge.

MATERIALS REQUIRED

Metre bridge (slide wire bridge), Leclanche cell or Battery eliminator, Galvanometer,

Resistance box , Jockey , One way key. A resistance wire, Screw gauge, Metre scale,

Connecting wires

THEORY

Resistors in Parallel

If the starting ends of two resistors are joined to a point and the terminal ends of the

two are combined and given connection to a source of electricity,those circuits are

called Parallel Circuit.

When the two resistors X1 and X2 are connected in parallel in a circuit, the potential

difference across X1 and X2 are the same

That is, for a set of parallel resistors, the reciprocal of their equivalent resistance

equals the sum of the reciprocals of their individual resistances. Thus, resistance

decreases in parallel combination.

CIRCUIT DIAGRAM


OBSERVATIONS

Table for length ( l ) and unknown resistance (X)

Resist

ance

coil

S.

No.

Resistanc

e from the

resistance

box R

ohm

Length

AD = l cm

Length

DC =

(100 - l)

cm

Resistance

xRl

lr

100

ohm

Mean

Resistance

in ohm

r1 only 1.

2.

3.

r2 only 1.

2.

3.

r1 and r2

in

parallel

1.

2.

3.

CALCULATIONS

• Calculation for verification of laws

• Experimental value of Rp =

• Theoretical value of Rp = r1r2/r1+r2

• Difference if any

RESULT

Within limits of experimental error, theoretical and experimental values are R s are

same. Hence law of resistance in series is verified.


PRECAUTIONS

1. The connections should be neat and clean.

2. Thick copper wires should be used for connections after removing the

insulations near their ends by rubbing with sand paper.

3. Plug key should be inserted only when the observations are to be taken.

4. Do not drag the jockey on the meter bridge wire.


EXPERIMENT…………… DATE:…………….

THE POTENTIOMETER-INTERNAL RESISTANCE OF A CELL

AIM

To measure the internal resistance of a given primary cell using potentiometer.

MATERIALS REQUIRED

Potentiometer, Battery eliminator, Two one way key, Rheostat of low resistance,

Galvanometer, Two resistance boxes, Leclanche cell, Jockey, Ammeter, Connecting

wires

THEORY

• Potentiometer is a device used to measure the internal resistance of a cell, to

compare the e.m.f. of two cells and potential difference across a resistor.

• It consists of a long wire of uniform cross sectional area and of 10 m in length.

The material of wire should have a high resistivity and low temperature

coefficient. The wires are stretched parallel to each other on a wooden board.

The wires are joined in series by using thick copper strips. A metre scale is

also attached on the wooden board.

• It works on the principle that when a constant current flows through a wire of

uniform cross sectional area, potential difference between its two points is

directly proportional to the length of the wire between the two points.

Relation between e.m.f., potential difference, and internal resistance of a cell

If a cell of emf E and internal resistance r, connected to an external resistance R, then

the circuit has the total resistance (R+r). The current I in the circuit is given by,

Using a potentiometer, we can adjust the rheostat to obtain the balancing lengths l1

and l2 of the potentiometer for open and closed circuits respectively. Then,

and

where k is the potential gradient along the wire.

Now we can modify the equation for getting the internal resistance of the given cell,

by using the above relations


CIRCUIT DIAGRAM

PROCEDURE


connection diagram. Tight the plugs of the resistance box. To test the

connection, insert the key k 1 and note the ammeter reading. Introduce a

sufficiently high resistance on the resistance box (H.R). Place the jockey at the

two end points of the wire. If the galvanometer shows opposite deflection, then

the connections are correct.

2. Without inserting the key k2, slide the jockey along the potentiometer wire and

stops when null point is obtained. Measure the balancing length l1 between this

point and the end P of the potentiometer.

3. Now, introduce plugs in keys k1 and k2. Take out a small resistance from the

resistance box R connected in parallel with the cell.

4. Again slide the jockey along the potentiometer wire to obtain the null point.

Measure the new balancing length l2 based on this point. Reduce the value of

R successively and in each time, measure the balancing length.

5. Keep the reading on the ammeter constant throughout the observation.

OBSERVATIONS

S.

No.

Ammeter

Reading

(A)

Position of null point (cm) Shunt

Resistance R

Ohm

Internal

Resistance

r= xRl

ll

2

21

Ohm

Without shunt

l1

With Shunt l2

1.

2.


CALCULATIONS

Calculate the value of r for each set of l1 and l2. The mean of the calculated values

gives the internal resistance (r) of the given cell.

RESULT

The internal resistance of the given primary cell, r = ..……….. Ω.

PRECAUTIONS

1. The EMF of the primary (driver ) cell must be greater than the EMF of the cell

whose internal resistance is to be measured

2. The positive terminal of all the cells must be connected to the same terminal of

the potentiometer

3. The high resistance box, connected adjacent to galvanometer is for its safety so

high resistance plug should always be taken out from the resistance box before

the jockey is moved along the wire.


EXPERIMENT No.………………. DATE:………….

THE POTENTIOMETER COMPARISON OF EMFs OF TWO CELLS

AIM

To compare the emf’s of two given primary cells using a potentiometer.

MATERIALS REQUIRED

Potentiometer, Daniel cell, Leclanche cell, Jockey, Battery eliminator, Resistance

box, Galvanometer, One way key, Two way key, Rheostat, Ammeter, Connecting

wires

THEORY

• Potentiometer is a device used to compare the e.m.f. (electromotive force) of two

cells, to measure the internal resistance of a cell, and potential difference across a

resistor.

• The potentiometer works on the principle that when a constant current flows

through a wire of uniform cross sectional area, potential difference between its two

points is directly proportional to the length of the wire between the two points.

• Electromotive force (e.m.f) of a cell.: It is defined as the potential difference across

the terminals of a cell, when no current flows through it. Electromotive force is also

known as voltage, and it is measured in volts. Electromotive force is not truly a force;

rather, it is a measurement of energy per unit charge.

Using a potentiometer, we can determine the emf of a cell by obtaining the balancing

length l. Here, the fall of potential along the length l of the potentiometer wire is

equal to the emf of the cell, as no current is

being drawn from the cell. Then, OR

where k is the potential gradient of the wire

Thus it is possible to compare the emf’s of two given cells by measuring the

respective balancing lengths l1 and l2.

or

CIRCUIT DIAGRAM


PROCEDURE


connection diagram. Tight the plugs of the resistance box. Note the reading on

the ammeter.

2. To test the connection, insert plug in the one way key k1 and also in between

the terminals a and c of the two way key. Introduce a sufficiently high

resistance on the resistance box (R.B).

3. Place the jockey at the two end points of the wire. Press the jockey at both end

of the potentiometer wire and note the deflection in galvanometer.

4. If the galvanometer shows opposite deflection, the connections are correct.

5. Now, gently slide the jockey along the potentiometer wire and stop when null

point is obtained.

6. Measure the length l1 between this point and the end P of the potentiometer. It

is the balancing length for the cell E1.

7. Disconnect the cell E1 by removing the plug from the gap ac of the two way

key and connect the cell E2 by inserting plug into the gap bc of the two way

key.

8. Again slide the jockey along the potentiometer wire to obtain the null point.

Measure the new balancing length l2 for the cell E2 based on this point. Make

sure that the reading on the ammeter is constant throughout the observation.

9. Repeat the experiment by increasing the current by adjusting the rheostat and

record the observations.

10. Each time, the ratio between the emf’s of the given cells can be calculated

using the relation

Range of the Ammeter = _________A

Least count of the Ammeter = _________A

Range of Voltmeter =__________V

Least count of the Voltmeter =___________V

EMF of Battery Eliminator E=__________V

EMF of Leclanche Cell = E1= __________V

EMF of Daniel Cell = E2 = __________V


OBSERVATIONS

S.No. Ammeter Reading (A) Balance Point E1/E2 = l1/l2

When E 1

(Leclanche

Cell) in the

circuit (l1 cm)

When E 2

(Daniel Cell)

in the circuit

(l2 cm)

1.

2.

CALCULATIONS

Calculate the ratio of E1 and E2 for each set of l1 and l2. The mean of the calculated

values gives the ratio of emf’s of the two given primary cells.

RESULT

1. The emf’s of the two given primary cells are compared.

2. The ratio of emf’s of the two given primary cells, = ____________

PRECAUTIONS

1. The EMF of the primary (driver ) cell must be greater than the EMF of the cell

whose internal resistance is to be measured.

2. The positive terminal of all the cells must be connected to the same terminal of

the potentiometer

3. The high resistance box, connected adjacent to galvanometer is for its safety so

high resistance plug should always be taken out from the resistance box before

the jockey is moved along the wire.


EXPERIMENT NO: ……………….. DATE:……………..

RESISTANCE OF A GALVANOMETER AND FIGURE OF MERIT

AIM

To determine the resistance of a galvanometer by half deflection method and to find

its figure of merit.

MATERIALS REQUIRED

A weston type galvanometer, A battery or battery eliminator, Two resistance boxes,

Two one-way keys, Connecting wires

THEORY

• A galvanometer is a device used to detect feeble electric currents in a circuit. I

• t consists of a coil suspended between the poles of a powerful magnet.

• As current passes through the coil, it deflects. It can be detected from the deflection

on galvanometer needle.

• The deflection is proportional to the current passed through it.

Resistance of galvanometer by half deflection method

Here, current will flows through th circuit when key k1 is closed and k2 is open. The

current flowing through the galvanometer is proportional to the deflection in it.

When k2 is closed and by adjusting the shunt resistance S, we can make

galvanometer deflection as θ/2. Then the current in the circuit is ;

Now, a fraction,

of the current in the circuit is flows through the galvanometer, which is given by,

Now, from the above relations, we can get the resistance of the given galvanometer

as,

Figure of merit of a galvanometer.

The figure of merit of a galvanometer is the current required to produce a deflection

of one division in the

galvanometer scale. It is represented by the letter k, and is given as, OR


CIRCUIT DIAGRAM

PROCEDURE

Resistance of galvanometer by half deflection method

1. Arrange the components on a table and connect them as per the circuit diagram.

2. Make sure that plugs of the resistance boxes are tight.

3. Take out a high resistance from the resistance box 1 and insert the key k 1.

4. Adjust the resistance from this resistance box to get maximum galvanometer

deflection.

5. Note the deflection and record it as θ in the tubular column.

6. Insert the key k2 also, without changing the value on the resistance box.

7. Now, adjust the resistance from the low resistance box such that galvanometer

shows deflection which is exactly half of the previous reading.

8. Record the value of low resistance box.

9. We can repeat the experiment by changing the value of high resistance R and

adjusting low resistance S.

10. The resistance of the given galvanometer can be calculated each time by using the

relation


Figure of merit of the galvanometer

1. Release key k2 from the connection. Insert key k1.

2. Adjust the value of R such that the galvanometer shows a certain deflection.

3. Record the observations in a tabular column.

4. Repeat the experiment by changing the value of R and note the galvanometer

deflection each time.

5. We can find the figure of merit of the galvanometer by using the equation, k=

E/(R+G)θ.

OBSERVATIONS

a. Resistance of galvanometer by half deflection

S.No. Resistance

R ohm

Deflection in

the

Galvanometer

Ɵ

Shunt

Resistance

S ohm

Half

Deflection

Ɵ/2

Balvanometer

Resistance

G = SR

RS

Ohm

1 30º

2 20º

3 10º

b. Figure of merit of Galvanomter

S.No. EMF E(V) in

Battery

Eliminator

Resistance from

Resistance Box R

Ohm

Deflection Ɵ

(div)

Figure of merit

k= )( GR

E

A/div

1 30

2 30

3 30


CALCULATIONS

• Calculate the value of G in each case and record it in the tabular column. The mean

of these calculated values will give the resistance of the given galvanometer.

• Calculate the value of k in each case and record it in the tabular column. The mean

of these calculated values will give the figure of merit of the given galvanometer.

RESULT

• The resistance of the given galvanometer, G =_________Ω

• The figure of merit of the given galvanometer, k =_________ Amp / div

PRECAUTIONS

1. All the connections should be neat and clean

2. All the plugs in resistance boxes should be tight

3. The EMF of battery should be constant

4. Initially a high resistance from the resistance box should be introduced in the

circuit otherwise an excessive current will flow through the galvanometer and

damage it.


EXPERIMENT No. …………………………. DATE:………………

FOCAL LENGTH OF A CONVEX LENS

AIM

To find the focal length of the given convex lens (i) by u-v method , (ii) by u-v graph

and (iii) by 1/u- 1/v graph

MATERIALS REQUIRED

Convex lens, screen, Illuminated wire gauze., Metre scale

THEORY

• Convex lens : It is thicker at the middle and thin at the ends.

• Convex lens are also called converging lens because it converges all parallel beam

of light incident on it.

• Convex lens can form real images as well as virtual image

Lens Formula

The equation connecting the distance between lens and object (u), distance between

lens and image (v), and the focal length of the lens (f) is called lens formula.

• The focal length of the convex lens, f = uv/u+v (using sign convention)

RAY DIAGRAM

MODEL GRAPH


PROCEDURE

By distant object method :

1. Fix the given convex lens on the stand and place it on a table, facing towards a

distant object.

2. Arrange the screen on the table so that the image of the distant object is

obtained on it.

3. Measure the distance between lens and screen using a metre scale. It can be

taken as the rough focal length (f) of the lens .

By u-v method :

1. Using the focal length obtained by distant object method set the values of u

(distance between lens and object) ranging from 1.5f to 2.5f. Divide the range

into a number of equal steps.

2. Place the lens in front of an illuminated wire gauze. It acts as the object

3. Now, fix the lens at the distance u (which is obtained as 1.5f) from the wire

gauze.

4. Place the screen on the table behind the lens in such a way that the refracted

image lies on the screen.

5. We can adjust the position of the screen to get the clear image of the wire

gauze.

6. Keeping the distance between object and lens fixed, adjust the position of

screen in order to get the clear image of the object.

7. Measure the distance between lens and wire gauze, as well as lens and screen.

Take these values as u and v respectively. Record the values of u and v in a


tabular column.

8. Calculate the focal length of the given convex lens by using the relation,

9. Repeat the experiment for different values of u (up to 3f) and in each time,

measure v and record it in the tabular column.

10. Calculate the focal length (f) of the convex lens each time. Calculate the mean

of all focal lengths to get the correct focal length of the given convex lens.

OBSERVATIONS

The rough focal length of the convex lens = ___________cm

S.No.

Object

Distance

u(cm)

Image

distance

v(cm)

f= uv/(u-v)

cm

1/u cm-1

1/v cm-1

1

2

3

4

5

6

(Note: For convex lens u = negative v= positive)

CALCULATIONS

• Calculate the value of focal length (f) each time and find its mean.

• Plot a graph with u along -X axis and v along Y axis by taking same scale for

drawing the X and Y axes. Draw the bisector OA and join OC and OB. Thus,

OC=OB= 2f. Calculate the focal length from this.

• Plot a graph with 1/u along X axis and 1/v along Y axis by taking same scale for

drawing the X and Y axes. The graph is a straight line intercepting the axes at A and

B. Then OA=OB= 1/f. Calculate the focal length from this.

RESULT

The focal length of the given convex lens, f

1. By u-v method = ___________ cm

2. From u-v graph, f = _________cm.


3. From 1/u- 1/v graph, f = ____________cm.

PRECAUTIONS

1. Lens , screen and object must be in line

2. Avoid parallax error while taking measurements

3. The object needle should be placed at such a distance that only real inverted image

of it is formed.

4. Index correction of u and v should be applied


EXPERIMENT NO:………………….. DATE:…………….

FOCAL LENGTH OF A CONCAVE MIRROR

AIM

To find the focal length of the given concave mirror by finding image distance (v) for

various values of (u).

MATERIALS REQUIRED

Concave mirror, Stand, Screen, Illuminated wire gauze., Metre scale

THEORY

• Concave mirror: Its inner concave surface reflects, and has polished outer

surface

• Concave mirrors have the reflecting surface that bulges inward. They are also

called converging mirrors because it converges all parallel beam of light

incident on it.

• Unlike a flat mirror, concave mirrors can form real images that are projected

out in front of the mirror at the place where the light focuses.

• Concave mirrors can be used in satellite dishes, vehicle headlights,

astronomical telescopes and many more areas.

Mirror Formula

The equation connecting the distance between mirror and object (u), distance

between mirror and image (v), and the focal length of the mirror (f) is called mirror

formula.

1/f = 1/v + 1/u

The focal length of the concave mirror,

RAY DIAGRAM


PROCEDURE

By distant object method :

• Fix the given concave mirror on the stand and place it on a table, facing towards a

distant object.

Arrange the screen on the table so that the image of the distant object is obtained on

it. Measure the distance between mirror and screen using a metre scale. It can be

taken as the rough focal length (f) of the mirror

By u-v method

• Using the focal length obtained by distant object method set the values of u

(distance between mirror and object) ranging from 1.5f to 2.5f. Divide the

range into a number of equal steps

• Place the mirror in front of an illuminated wire gauze. It acts as the object

• Now, fix the mirror at the distance u (which is obtained as 1.5f) from the wire

gauze.

• Place the screen on the table facing the mirror in such a way that the reflected

image lies on the screen.

• Adjust the position of the screen to get the clear image of the wire gauze.

• Keeping the distance between object and mirror fixed, adjust the position of

screen in order to get the clear image of the object.

• Measure the distance between mirror and wire gauze, as well as mirror and

screen. Take these values as u and v respectively. Record the values of u and v

in a tabular column.

• Calculate the focal length of the given concave mirror by using the relation, f =

uv/(u+v).

• Repeat the experiment for different values of u (up to 2.5f) and in each time,

measure v and record it in the tabular column.

• Calculate the focal length (f) of the concave mirror each time. Calculate the

mean of all focal lengths to get the correct focal length of the given concave

mirror.


OBSERVATIONS

The rough focal length of the given concave mirror ____________ cm.

S.No. Object distance

–u cm

Image distange

- v cm

Focal length of

concave mirror f in

cm

1

2

3

4

RESULT

• The focal length of the given concave mirror (f)= __________ cm

PRECAUTIONS

1. Mirror , screen and object must be in line

2. Avoid parallax error while taking measurements.

3. Index correction for u and v should be applied.


EXPERIMENT No. …………………….. DATE:…………….

FOCAL LENGTH OF CONVEX MIRROR

AIM

To find the focal length of a convex mirror using a convex lens.

MATERIALS REQUIRED

Illuminated wire gauze, Stand, Screen, Meter scale, Convex lens, Given convex

mirror

THEORY

• A convex mirror is a curved mirror in which the reflecting surface bulges

towards the light source. Convex mirrors reflect light outwards; therefore they

are not used to focus light. A convex mirror is also known as fish eye mirror or

diverging mirror.

• The image formed by a convex lens is virtual and erect, since the focal point

(F) and the centre of curvature (2F) are both imaginary points "inside" the

mirror that cannot be reached. As a result, images formed by these mirrors

cannot be projected on a screen, since the image is inside the mirror.

Therefore, its focal length cannot be determined directly.

• The image is smaller than the object, but gets larger as the object approaches

the mirror. The focal length of a convex mirror can be determined by

introducing a convex lens between the object and the convex mirror. An image

can be obtained with the help of a convex lens side by side with the object

when the convex mirror reflects the rays along the same path, i.e., when the

rays fall normally on the mirror. Then, the radius of curvature, R, of the mirror

is the distance between the screen and the mirror.

RAY DIAGRAM

The focal length f of the convex mirror is calculated using the formula,


PROCEDURE

1. Place a convex lens on a stand facing the illuminated wire gauze at a fixed

distance, say 35 cm, away from the wire gauze

2. Place a screen, at the other side of the lens so that the wire gauze, lens and

screen are in a straight line. Adjust the position of screen to get a clear image

of the wire gauze.

3. Now fix the given convex mirror to another stand and place it in between the

convex lens and screen with its reflecting face facing the wire gauze.

4. Now place another side by side with the wire gauze.

5. The position of the convex mirror is adjusted so that a clear image of the wire

gauze is formed on the screen placed side by side with the wire gauze.

6. Measure the distance between the mirror and first screen and take as the radius

of curvature of the mirror R. The focal length of the mirror is calculated as ,

OBSERVATIONS

S.No.

Distance from lens to Radius of

curvature, R

(cm)

Focal length of

the Convex

Mirror – cm

f= R/2

Object u (cm) Image v (cm)

1

2

3

CALCULATIONS

• Calculate the mean focal length of the convex mirror.

• Focal length of the convex mirror, Mean (f) = ____________cm

RESULT

The focal length of the given convex mirror = ___________.cm

PRECAUTIONS

1. The uprights supporting the pins, lens and mirror must be rigid and mounted

vertically

2. Eye should be placed at a distance of about 25 cm or more from the image pin.

3. Tip to Tip parallax should be removed.

4. Index correction should be applied between the image needle I and back

surface of the convex mirror.


EXPERIMENT No…………………… DATE:…………….

REFRACTION THROUGH A PRISM

AIM

To study the angle of deviation (d) with angle of incidence (i) and to find the angle of

minimum deviation (D) from i-d curve.

MATERIALS REQUIRED

Glass prism, Drawing board, Paper, Pins. Scale, Pencil, Protractor

THEORY

• A prism is an optical element. It has polished flat surfaces that refract light.

The traditional geometric shape of a prism has a triangular base and two

rectangular sides. It is called triangular prism.

• A ray of light suffers two refractions on passing through a prism. If KL be a

monochromatic light falling on the side AB, it is refracted and travels along

LM. It once again suffers refraction at M and emerges out along MN. The

angle through which the emergent ray deviates from the direction of incident

ray is called angle of deviation 'd'.

• As the angle of incidence is increased, angle of deviation 'd' decreases and

reaches minimum value. If the angle of incidence is further increased, the

angle of deviation is increased.

• A graph is drawn between angle of incidence (i) and angle of deviation (d) by

taking angle of incidence (i) along X-axis and angle of deviation (d) along Y-

axis. It should be a curved graph.

RAY DIAGRAM


MODEL GRAPH

PROCEDURE

1. Fix a paper on the drawing board placed on the table. Place the given glass

prism on the center of the paper Using the pencil, mark the outline ABC of the

prism on the paper.

2. Remove the prism, and using the scale and pencil, normal N1O is drawn to the

face AB at the point L. Using the protractor, measure an angle 30° from the

normal.

3. Another line KL is drawn at L making the angle 30° (angle of incidence i) with

the normal N 1O

4. Two pins R1 and R2 are fixed on this line.. The prism is replaced on the

outline ABC.

5. Viewing the pins from the face AC of the prism, two other pins R3 and R4 are

fixed so that R1, R2, R3 and R4 are in a line. Remove the pins

6. A line NM is drawn to meet on the face AC through the marks of R3 and R4.

7. The line LM is joined. The line KL is extended to get the LQ and NM is

extended to get the line MP. These two lines meet at P. Using the protractor,

measure the angle QPM. This is the angle of deviation d.

8. Repeat the experiment for different values of angle of incidence (i) and the

corresponding angle of deviations are measured.

9. Draw a graph with angle of incidence (i) along the X-axis and angle of

deviation (d) along the Y – axis. The angle of deviation corresponding to the

lowest bend of the curve is the angle of minimum deviation (D).


OBSERVATIONS

Angle of the prism A = -----

S No Angle of incidence (i) Aangle of deviation (d)

1 30º

2 35º

3 40º

4 45º

5 50º

6 55º

RESULT

• A graph showing the variation of angle of deviation with the angle of incidence

is plotted.

• Angle of minimum deviation, D = --------°

PRECAUTIONS

1. Distance between the two pins should not be less than 10mm.

2. The same angle of prism should be used for all the observations.

3. Arrow heads should be marked to represent the incident & emergent rays.


EXPERIMENT No…………………… DATE:………………..

FOCAL LENGTH OF CONCAVE LENS

AIM

To find the focal length of concave lens using convex lens

MATERIALS REQUIRED

Illuminated wire gauze, two lens stand, Screen, Metre scale, A convex lens of short

focal length, Concave lens

THEORY

• A concave lens is thinner at the center that at the edges. So the light beams

passing through the lens are spread out or diverged. Therefore, the concave

lens is called a diverging lens. The image formed by a concave lens is virtual

and diminished.

• Since a concave lens will not produce a real image, a convex lens is used to

measure its focal length.

• The real image (I1) formed by the convex lens will act as the virtual object for

the concave lens. When concave lens is interposed between the convex lens

and the real image I1, the new real image is formed at I2. If u is the distance of

the concave lens from the virtual object I1 and v is the distance of the concave

lens from the real image I2, then the focal length of the given concave lens is,

RAY DIAGRAM


PROCEDURE

1. The given convex lens is mounted on a stand. It is placed between the

illuminated wire gauze and the screen at a fixed distance away from the wire

gauze

2. The position of the screen is adjusted to get a clear image of the wire gauze on

the screen at I 1.

3. Now, the given concave lens (L) is mounted between the screen and the

convex lens without any rearrangement.

4. The distance between the screen and the concave lens LI1 is measured as u cm.

Now, the screen alone is moved back to obtain a clear image I 2 on the screen.

5. The distance between the concave lens and the screen, LI 2 is measured as v

cm.

6. Using the values of u and v, the focal length of the concave lens is calculated

using the formula, f= uv/u-v.

7. To repeat the experiment, remove the concave lens and bring the screen to the

initial position. Then place the concave lens at a different position in between

the convex lens and screen and record the values in the tabular column.

OBSERVATIONS

CALCULATIONS

Focal length of concave lens, Mean f = ___________cm

RESULT

The focal length of the concave lens by combination method = ____________cm

PRECAUTIONS

1. Focal length of convex lens should be less than focal length of concave lens so

that the combination is convex.

2. The lenses must be clean.

3. The object needle should be placed at such a distance that only real inverted

image of it is formed.

S NO Distance between concave lens and

Focal length of

concave lens

cm

f = uv/(u-v)

First image I1

(u cm)

Second image I2

(v cm)

1

2

3


EXPERIMENT No. ………………. DATE:………….

REFRACTIVE INDEX OF A GLASS SLAB

AIM

To determine refractive index of a glass slab using a travelling microscope

MATERIALS REQUIRED

Glass slab, travelling microscope or lycopodium powder

THEORY

• P is a point mark (object) at the bootom of the slab. A ray of light PQ from P is

incident at the top at the point Q at an angle of incidence I and refracts along

QR at an angle r. It appears to come from P1. P1 is the virtual image of real

object P formed on normal PSN.

PS is the real thickness of the slab.

P1S is the apparent thickness of the slab.

Calculation

In SP1Q SPQ = i (being alternate angle of i)

Sin i = PQ

SQ

In SP1Q SP1Q = r (being corresponding angle of r)

Sin r = QP

SQ

1

From Snell’s law,


For light going from glass to air

PQ

QP

QPSQ

PQSQ

r

inag

1

1/

/

sin

sin

or QP

PQn

ag

ga

1

1

For a ray received normally along PSN, Q is very close to S.

Then PQ = PS and P1Q = P1S

and icknessApparentth

salthicknes

SP

PSnga

Re

1

labicknessofsApparentth

sofslabalthicknesnga

Re

This is an important relation. It is used for determination of refractive index of

the material of the transparent glass slab.

DIAGRAM

PROCEDURE

1. Place the travelling microscope with adjustment of light and level.


2. Make a black ink cross mark on the base of the microscope (point P)

3. Focous on point P and take readings of the main scale and vernier scale

reading (R1)

4. Place the glass slab over the mark P, focous it a (point P1 and take the reading

R2)

5. Sprinkle lycopodium powder on the surface of the slab and focus the point near

S take the reading (R3)

OBSERVATIONS

Serial

No.

Reading on vertical scale when

microscope is focussed on

Real

thickness

(R3-R1)

(cm)

Apparent

thickness

(R3-R2)

(cm)

Refractive

index

n= 23

13

RR

RR

Cross-

mark

without

slab R1

(cm)

Cross-

mark with

slab R2

(cm)

Lycopodium

powder R3

(cm)

1.

2.

CALCULATIONS

• Calculate the refrective index of the material of slab.

RESULTS

The refractive index of material of the slab is-

PRECAUTIONS

1. In microscope, the parallax should be properly removed.

2. The microscope should be moved in upper direction only to avoid back lash

error.



REFRACTIVE INDEX OF A LIQUID

AIM

To find refractive index of liquid by using a convex lens and plane mirror

MATERIALS REQUIRED

A convex lens of plane mirror, clean transparent liquid, an optical needle and iron

stand with base and clamp arrangement half meters scale.

THEORY

• Let the convex lens be of RI = 1.5

* Now

21

11)1(

1

RRn

f vex

21

11)15.1(

1

RRf vex

21

11)5.0(

1

RRf vex

Rf vex

2)5.0(

1

Rf vex

11

Therefore focal length of convex lens = R

* Liquid lens formed between convex lens and plane mirror is plano concave

* So

21

11)1(

1

RRn

f liq

11)1(

1

1Rn

f liq

, 1. One surface plane, so R1 =

2. One surface concave: Radius of curvature of

convex lens R of this surface is R of convex

lens


R

n

f liq

11

* We no that for a combination, focal length of combination is

1/Fcomb. =

1/f1 + 1/f2,

where f1-convex lens, f2 liquid plano convex lens

1/Fcomb. =

1/R-(n-1)/R, but R=fvex

1/Fcomb. = 1/R (1-n+1) = (2-n)/R

2-n = R/Fcomb.

n = 2-(R/Fcomb.)

DIAGRAM

PROCEDURE

1. Fine the rough focal length of the given convex lens

2. Keep a plane mirror 4”x4” on the horizontal base of the iron stand and then

place the convex lens over the plain mirror.

3. Screw tight the optical needle in the clamp of the stand and hold it horizontally

above the lens at distance equal to extra focal length.

4. Focus the needle & it image without parallax, as seen from above the needle

5. Measure distance between needle tip and surface of the plane mirror.

6. Now put a few drops of liquid in between the plane mirror and convex lens (a

plano coave liquid lens is formed between plane mirror and convex lens) and

focus the needle and its immage.

7. Take the readings.


OBSERVATIONS

Rough focal length of convex lens = - cm

Table for distance of needle tip from lens & mirror

Arrangement From lens

surface X1

(cm)

From plane

mirror X2

(cm)

Mean

2

21 xxX

cm

Focal length X

(cm)

Without liquid

With liquid

CALCULATIONS

n = 2-(R/Fcomb.)

• Calculate the refrective index of the liquid using the above formula

RESULTS

The refractive index of liquid is= -

PRECAUTIONS

1. The liquid taken should be transparent.

2. Only few drops of liquid should be taken so that its layer is not thick.

3. The parallax should be removed tip to tip.



DIODE CHARACTERISTICS

AIM

To draw the characteristics curve of p-n junction diode in forward bias and reverse

bias

MATERIALS REQUIRED

A p-n junction diode, 3 V battery, 50 V battery, High resistance rheostat, 0-3 V

voltmeter, 0-50 V voltmeter, 0-100 mA ammeter, 0-100 µA ammeter, One way key,

Connecting wires.

THEORY

• Biasing in general means the application of dc voltage across the terminals of a

device for a particular operation. Two types of biasing are possible in a p-n

junction diode. They are; Forward Biasing and Reverse Biasing

• Forward biasing occurs when the positive end of the diode is connected to the

positive terminal of the battery, and its negative end to the negative terminal of

the battery. Here, majority carriers from both sides move towards and cross the

junction and current flows through the junction. This current is known as the

forward current and is the order of 10-3 A. The size of the depletion layer

decreases in forward biasing.

• Reverse biasing occurs when the positive end of the diode is connected to the

negative terminal of the battery, and its negative end to the positive terminal of

the battery. Here, majority carriers from both sides move away from the

junction and thus no current flows through the junction. A very small current

will made at the junction due to the movement of minority charge carriers

across the junction

Characteristics of a p-n junction diode

• It generally shows the relation between bias voltage and current of a diode.

• The V-I characteristics of a diode can be forward or reverse. The graph

showing the forward bias voltage and forward current is known as the forward

characteristics, and that showing the reverse bias voltage and reverse current is

known as the reverse characteristics.

• The forward characteristics of a diode is non linear. The forward current

increases slowly in the beginning and shows a sudden rise at a certain value of

forward voltage. This voltage is known as the threshold voltage or Knee

voltage. This is because the resistance is very low in forward biased condition.


• The current in the reverse bias is due to the flow of minority carriers. The

reverse current shows a sudden increase at a particular region. The

corresponding voltage is termed as the reverse breakdown voltage.

CIRCUIT DIAGRAM

MODEL GRAPH

PROCEDURE

Forward I-V characteristics

1. Connections are made as per the connection diagram.

2. Insert the key. Arrange the sliding contact of the rheostat to minimum. Now,

gently move the rheostat contact to provide a positive bias voltage. Note the

voltmeter and milli ammeter readings.

3. Repeat the process by increasing the forward current in equal steps by

changing the rheostat slider.

4. It can be noted that, initially the current increase very slowly. For a certain

value of voltage, it shows a sharp increase. The corresponding voltage

represents the knee voltage of that diode.

5. Plot a graph with forward voltage along X axis and forward current along Y

axis. The graph shows the forward V-I characteristics of the given p-n junction

diode.


Reverse I-V characteristics

1. Make the circuit diagram as shown in the figure.

2. Insert the key. Arrange the sliding contact of the rheostat to maximum.

3. Move the sliding contact of the rheostat to provide a reverse bias voltage.Note

the voltmeter and micro ammeter readings Note the voltmeter and micro

ammeter readings

4. Repeat the process by changing the reverse voltage in equal steps.

5. The current increases slowly in the beginning and then rapidly when the

reverse voltage becomes a certain value. This voltage is known as the reverse

breakdown voltage.

6. Plot a graph with reverse voltage along X axis and reverse current along Y

axis. The graph shows the reverse V-I characteristics of the given p-n junction

diode.

OBSERVATIONS

Reverse I-V Characteristics

• Least count of voltmeter = ___________V

• Zero error of voltmeter = _____________V

• Least count of milli-ammeter = .__________mA

• Zero error of milli-ammeter = ____________.mA

Forward I-V Characteristics

S No Forward bias voltage VF

(V)

Forward bias current

IF

1

2

3

4

5

6

7

8

9


10

S NO REVERSE BIAS VOLTAGE

VR (V)

REVERSE BIAS

CURRENT IR (μA)

1

2

3

4

5

6

7

9

10

11

12

13

14

15

CALCULATIONS

• For the forward characteristics of the given p-n junction diode, a graph is

plotted with forward voltage along X axis and forward current along Y axis.

The forward current shows a sudden increase at certain forward voltage, which

is known as the knee voltage.

• For the reverse characteristics of the given p-n junction diode, a graph is

plotted with reverse voltage along X axis and reverse current along Y axis. I t

is noted that at a certain reverse voltage, the reverse current reaches its

maximum level. Further increase in voltage does not increase this current. It is

the reverse saturation current. However, with further increase in reverse

voltage, the current shows a rapid rise at a certain value. It is known as the

reverse breakdown voltage.

RESULTS

The forward and reverse characteristics of the given p-n junction diode is drawn.

PRECAUTIONS

1. While doing the experiment do not exceed the readings of the diode. This may

lead to damaging of the diode.

2. Connect voltmeter and ammeter in correct polarities as shown in the circuit

diagram

3. Reverse bias voltage beyond breakdown should not be applied.


EXPERIMENT NO…………….. DATE:…………….

ZENER DIODE CHARACTERISTICS

AIM

To draw the reverse characteristic curve of a Zener diode and to find its reverse

breakdown voltage.

MATERIALS REQUIRED

Battery, Rheostat, Small resistance (200 Ω), Milliammeter, Voltmeter, Key, Zener

diode

THEORY

• A Zener diode is a heavily doped silicon crystal diode which allows current to

flow in the forward direction in the same manner as an ideal diode. It also

permits the current to flow in the reverse direction when the voltage is above a

certain value known as the breakdown voltage. Breakdown voltage is also

known as Zener knee voltage.

Working of Zener diode

• As the reverse voltage applied to the Zener diode increases, it reaches the

breakdown voltage at which Zener current increases to a large value. In the

breakdown region, further increase in reverse voltage will not increase the

voltage across the Zener diode, it only increases the current. Thus, a constant

voltage called Zener voltage (Vz) is maintained across the Zener diode when

the supply voltage changes. Hence, it acts as a voltage regulator.

• The reverse characteristic is obtained by taking reverse voltage along – ve X-

axis and reverse current along –ve Y-axis. As the reverse voltage reaches a

certain value, the reverse current increases to a large value, but the voltage

across the diode remains a constant. This is the break down voltage Vz.

CIRCUIT DIAGRAM


MODEL GRAPH

PROCEDURE

• Connections are made as shown in the circuit. By adjusting the rheostat,

voltmeter reading is increased from 0 and in each time note the corresponding

reading in milliammeter.

• The experiment is continued till the milliammeter shows a large deflection

while the voltmeter reading remains a constant, indicating the break down

voltage.

• Plot the reverse characteristic curve by taking reverse voltage along –ve X-axis

and reverse current along–ve Y-axis.

• The break down voltage Vz is obtained from the graph as shown above.

OBSERVATIONS

• Least count of voltmeter =_____________V

• Zero error of voltmeter =______________.V

• Least count of micro-ammeter = _________A

• Zero error of micro-ammeter = ___________A

S NO Reverse bias voltage VR

(V)

Reverse bias current IR

(A)

1

2

3

4


5

6

7

8

9

10

11

12

13

14

15

16

CALCULATIONS

Plot the reverse characteristic curve by taking reverse voltage along –ve X-axis and

reverse current along –ve Y-axis.

RESULT

• The reverse characteristic curve of the Zener diode is obtained

• The reverse breakdown voltage of the Zener diode, V = ___________V

PRECAUTIONS

1. Connect voltmeter and ammeter in correct polarities as shown in the circuit

diagram.

2. Do not switch ON the power supply unless you have checked the circuit

connections as per the circuit diagram.

3. Zener diode should be connected reverse bias.



ACTIVITY NO

DATE:

AIM

To assemble a household circuit comprising three bulbs, three (on/off) switches, a

fuse and a power source

MATERIALS REQUIRED

Three bulbs(6V,1 W) each, fuse of 0.6 A, main switch, a power supply (battery

eliminator), three (on/off) switches, flexible connecting wire with red and plastic

covering, a fuse wire Supplementary: Main electric board with a two-pin socket and a

main switch.

THEORY

• Electric power supplied to us for domestic purposes is 220V AC and 50 Hz. The

household circuit, all appliances are connected in parallel with mains.

• The switches are connected in series with each appliances in live wire. 5 A switches

are required for normal appliances like bulbs, fluorescent tubes fans etc. 15 a sockets

and switches are required for

heavy load appliances like refrigerator, air conditioner, geyser, hot plates etc .

• All appliances must have three wires called live, neutral and the earth. Total power

consumption P at a time P = P1 + P2 + P3 where P1, P2, P3 are the power drawn by

appliances.

• To protect the appliances from damage when unduly high currents are drawn fuse

of little higher rating, 10 to 20% higher than the current normally drawn by all

appliances. For further safety, a suitable value MAINS FUSE like rating 32 A is

connected in series with supply source

Procedure:

1. Connect the bulbs B1, B2 and B3 in series with switches S1, S2 and S3

respectively and connect each set of B_S in paralle with each other.

2. Connect main supply to a step down transformer (battery eliminator) to get

required voltage from

0 to 10 V ( 0, 2, 4, 6, 8 and 10 V). Connect the mains fuse M.S in series with the

power supply (battery eleiminator).

3. Connect an A C ammeter in series with the B-S set. Connect one end of power

supply to one end B-S set.


4. Check the circuit once again to ensure that household circuit is complete.Gradually

increase the current to 0.75 A. The fuse must burn off at 0.6A.


ACTIVITY NO DATE:

AIM

To assemble the components of a given electrical circuit

MATERIALS REQUIRED

A voltmeter, an ammeter of an appropriate range, battery, rheostat, one way key,

unknown resistance, connecting wires, sand paper.

CIRCUIT DIAGRAM

PROCEDURE

1. Connect the components as shown in circuit diagram.

2. Connect the ammeter in series with the resistor to measure the current.

3. Connect the voltmeter in paralle to the resistor to measure the potential difference.

4. Connect the switch in series with the battery.

5. The components in the electrical circuit are completed.

Utility:

It is used for measuring an unknown resistance.


ACTIVITY DATE:

AIM

To draw the diagram of a given open circuit comprising atleast a battery, a

resistor/rheostat, key, ammeter and voltmeter. Mark the components that are not

connected in proper order and correct the circuit aand also the circuit diagram.

MATERIALS REQUIRED

A battery eliminator or a battery (0 to 6 V), rheostat, resistance box (0 to 100 Ω), two

or one way key, D.C. ammeter (0-3) A and a D. C. voltmeter (0-3) V.

OPE CIRCUIT DIAGRAM

THEORY

An open circuit is one in which no current is drawn from the battery.

PROCEDURE

1. The following components are not connected in proper order in the open circuit

diagram. Voltmeter, rheostat, resistance coil, one way key, ammeter and battery.

2. Ammeter: It should be connected in series with the battery eliminator

3. Voltmeter: It should be connected in parallel with resistor.

4. Rheostat: It should be connected in series with the battery eliminator (in place of

resistance coil).

5. Resistance coil: It should be connected in parallel (in place of rheostat)

6. One way key: It should be connected in series to the battery eliminator.

CORRECT CIRCUIT DIAGRAM


RESULT

Identified the components that are not connected in proper order and the circuit is

redrawn correctly with the circuit components in proper orde


ACTIVITY NO DATE:

AIM

To identify a diode, an LED, a transistor, an IC, a resistor and a capacitor from mixed

collection of such items.

MATERIALS REQUIRED

Diode, LED, transistor, an IC, a resistor, a capacitor and a multimeter

THEORY

• For identification, appearance and working of each item will have to be considered.

• A diode is a two terminal device. It conducts when forward biased and does not

conduct when reverse based. It does not emit light while conducting.

• A LED is also a two terminal device. It also conducts when forward biased and does

not conduct when reverse biased. It emits light while conducting.

• A transistor is a three terminal device. The terminals represent emitter (E), base (B),

and collector(C).

• An IC (integrated circuit) is a multi terminal device in the form of chip.

• A resistor is also a two terminal device. It conducts from both the ends. It conducts

even when operated with AC voltage.

• A capacitor is also a two terminal device. It does not conduct when either forward

biased or reverse biased. Initially the multimeter shows full current when capacitor is

connected to a dc source but it decays to zero quickly.

DIAGRAM OF COMPONENTS

PROCEDURE

1. If the item has four or more terminals it is an IC chip.


of

2. It it has three terminals it is a transistor.

3. If it has two terminals, it may be diode, resistor or capacitor.

To identify them proceed as ahead.

1. Take the multimeter. Put the selector on resistance R of multimeter for checking

the continuity. The probe metal ends are inserted in marked on the multimeter as

common and positive. The other two ends of the probe must touch the two ends of

the device.

2. If the pointer moves when voltage is applied in one direction and does not move

when reversed and there is no light emission, it is a diode.

3. If the pointer moves when voltage is applied in one direction and does not move

when reversed and there is light emission, it is a LED.

4. If the pointer moves when voltage is applied in both ways (forward and reverse), it

is a resistor.

5. If the pointer does not move when voltage is applied either way (forward or

reverse), it is a capacitor.

OBSERVATIONS

S

N

o

Number of

legs

Name of

devce

Possible

current

flow

Name

device 1 More than 3 IC -

2 Three Transistor -

3 Two Capacitor,

diode, LED

or resistor

Unidirec

tional

emit no

light

Diode

Unidirec

tional

emit

light

LED

Both

directio

n

(steady)

Resistor

Initial

high but

decays

to zero

Capacit

or


ACTIVITY DATE:

AIM

To observe refraction and lateral deviation of a beam of light incident obliquely on a

glass slab.

MATERIALSREQUIRED

Glass salb, drawing board, white paper, drawing pins, alpins, protractor

THEORY

• When a ray of light (PQ) incident on the face AB of glass salb, then it bends

towards the normal since refrction takes place from rarer to denser medium.

• The refracted ray (QR) travel along straight line and incident on face DC of slab

and bends away from the normal since refraction takes place fromdenser to rarer

medium.

• The ray (RS) which comes out through face DC is called emergent ray.

• From the following diagram, the incident ray is paralle to the emergent ray i.e., I =e.

The emergent ray is laterally deviated from its original path (incident ray) by a

distance

•

CIRCUIT DIAGRAM

PRCEDURE

1. Fix a white paper sheet by drawing pins on a drawing board.

2. Take a glass slab and place in the middle of the paper and mark its boundary

ABCD.


3. Draw a normal at point Q on face AB and draw a line PQ making an angle I with

the normal. PQ will represent an incident ray.

4. Fix two pins at points 1 and 2 on the line PQ at distances 1 cm or more between

themselves.

5. See images of these pins through face DC and fix two more pins at points 3 and 4

(1 cm or more apart ) such that these two pins cover the images of first two pins, all

being along a straight line.

6. Remove the glass slab. Draw straight line RS through points 3 and 4 to represent

emergent ray. Join QR to represent refracted ray.

7. Draw normal at point R on face DC and measure angle e. It comes to be equal to

angle i.

8. Produce PQ forward to cut DC at T. Draw TU perpendicular to RS. Tu measures

lateral displacement d.

9. Now take another set for different angle of incident and measure the lateral

dispalcement.

OBSERVATIONS

S

NO

Ange of incidence

(i)

Angle of emergence

(i)

Difference if

any (i-e)

1

2

CONCLUSION

1. The angle of incidence (i) = The angle of emergence (e)

2. Lateral dispalcement increase with increase in thickness of glass slab.

3. The lateral displacement increases with angle of incidence.

Documents

PHYSICS PRACTICAL NOTE BOOK€¦ · ohm Mean Resistance in ohm r 1 only 1. 2. 3. r 2 only 1. 2. 3. r 1 and r 2 in parallel 1. 2. 3. CALCULATIONS • Calculation for verification of