Class -12

Date – 16-04-2020

Home Assignment

Subject - Business studies

Chapter – 4 (Planning)

Write and learn the understanding - based question 1 to 9 (1 marks).

Write and learn the understanding – based question 1 to 9 ( 3 marks).

Subject – Accountancy

Chapter-4 (admission of a partner)

Solve additional Question (136-146) And Multiple - Choice Question (1 – 12)

In your practice note book.

Subject - Economics

Chapter- 5 (Money)

(a). Write and Learn multiple choice question (1 to 18)

(b). Write and learn Information and concept – based questions (1 to 15)

Collect data for as per information given for the following:

1.How much money was in circulation before demonetization?

2. How much money back in system at the time of demonetization?

3. Total cost of printing new notes in demonetization?

Subject Class: 12th

Arts H.W(16/04/2020)

Geography: Learn and write Ch-2 long answer type question (5-8) PART-1 World Population :

Distribution, Density and Growth.

Phy. Edu.: Learn and write Ch-2 Sports and Nutrition. And write long answer type question (7-13) in F/C

notebook.

Class -12

Subject-Chemistry

Date-16/04/20)

Chapter- Chemical Kinetic

Assignment-3

(Do it in your practice notebook)

Q.1. State a condition under which a bimolecular reaction is kinetically first order

reaction.

Q.2. Write the rate equation for the reaction 2A + B ⎯ → C if the order of the

reaction is zero.

Q.3.How can you determine the rate law of the following reaction? 2NO(g) + O2

(g) ⎯ → 2NO2(g)

Q.4. For which type of reactions, order and molecularity have the same value?

Q.5. In a reaction if the concentration of reactant A is tripled, the rate of reaction

becomes twenty seven times. What is the order of the reaction?

Q.6.Derive an expression to calculate time required for completion of zero order

reaction.

Q.7.For a reaction A + B ⎯ → Products, the rate law is — Rate = k [A][B]3/2 Can

the reaction be an elementary reaction? Explain.

Q.8. For a certain reaction large fraction of molecules has energy more than the

threshold energy, yet the rate of reaction is very slow. Why?

Q.9. For a zero order reaction will the molecularity be equal to zero? Explain.

Q.10. For a general reaction A ⎯ → B, plot of concentration of A vs time is given

in

Fig. Answer the following question on the basis of this graph.

(i) What is the order of the reaction?

(ii) What is the slope of the curve?

(iii) What are the units of rate constant?

Class -12

Subject-Chemistry

(Solution of HW-15/04/20)

Chapter- Chemical Kinetic

Assignment-2

(Do it in your practice notebook)

Q.1.

A bimolecular reaction becomes rst order reaction when one of the reactants is in excess.

Q.2.

Ans. Molecularity of a reaction means the number of molecules of the reactants taking

place in an elementary reaction. Since at least one molecule must be present, so that

molecularity will be atleast one.

Q.3.

Ans. First order reaction.

Q.4.

Ans. 16 minutes.

Q.5.

Ans. A reaction which takes place in one step is called an elementary reaction.

Q.6.

Ans. 9 times

Q.7.

Ans. 30 mins.

MD. SR SEC SCHOOL, MANKROLA

CLASS: 12TH

SUBJECT : BIOLOGY

HOME ASSIGNMENTS DATE: 16/04/2020

CHAPTER: 4, REPRODUCTIVE HEALTH

Good morning everyone I hope you all are doing study well.

Today I am sending some questions which are very important for

examination basis.

1. What is the WHO’s interpretation of reproductive Health?

2. Why has the Government imposed a statutory ban on

amniocentesis?

3. Expand MTP and ICSI.

4. What does GIFT represents.

5. Enlist any three causes of infertility in Men And Women.

6. Differentiate between Mortality and Natality Rate.

7. Explain any one natural method of birth control.

8. What are STDs ? Mention any two of it.

MD SR. SEC. SCHOOL

GURUGRAM

HOME WORK

CLASS-XII

SUBJECT-MATH

TOPIC-CONTINUITY AND DIFFERENTIABILITY DATE-16 APRIL2020

RECAP OF THE MAIN POINT FROM LAST LECTURE:

Definition of Continuity

In Mathematically, A function is said to be continuous at a point x = a, if

limx→a f(x) Exists, and

limx→a f(x) = f(a)

It implies that if the left hand limit (L.H.L), right hand limit (R.H.L) and the value of the function at x=a exists and these parameters are equal to each other, then the function f is said to be continuous at x=a.

If the function is undefined or does not exist, then we say that the function is discontinuous.

Continuity in open interval (a, b)

f(x) will be continuous in the open interval (a,b) if at any point in the given interval the function is continuous.

Continuity in closed interval [a, b]

A function f(x) is said to be continuous in the closed interval [a,b] if it satisfies the following three conditions.

1) f(x) is be continuous in the open interval (a, b)

2) f(x) is continuous at the point a from right i.e. limx→af(x)=f(a)

3) f(x) is continuous at the point b from left i.e. limx→bf(x)=f(b)

Lets Work Out- Example: Check whether the function 4x2−12x−1 is continuous or not? Solution: At x=1/2, the value of denominator is 0. So the function is discontinuous at x = 1/2.

Fundamental Theorems of Continuity (i) If f and g are continuous functions, then

f ± g and fg are continuous.

cf is continuous, where c is a constant.

f/g is continuous at those points, where g(x) ≠ 0. (ii) If g is continuous at a point a and f is continuous at g(a), then fog is continuous at a.

(iii) If f is continuous in [a, b] , then it is bounded in [a, b] i.e. , there exist m and M such that m ≤ f(x) ≤ M, ∀ x ∈ [a, b] where m and M are called minimum and maximum values f(x) respectively in the interval [a, b].

(iv) If f is continuous in [a, b], then f assumes atleast once eve value between minimum and maximum values of f(x). Thus, a ≤ x ≤ b ⇒ m ≤ f(x) ≤ M or range of f(x) = [m, M], x ε [a, b].

(v) If f is continuous in its domain, then |f| is also continuous in it domain.

(vi) If f is continuous at a and f (a) ≠ 0, then there exists an ope interval (a — δ, a + δ) such that for all x ε (a — δ, a + δ), f (x) has the same sing as f(a).

(vii) If f is a continuous function defined on [a, b] such that f (a) an f (b) are of opposite sign, then there exists atleast one solution the equation f(x)= 0 in the open interval (a, b).

(viii) If f is continuous on [a, b] and maps [a, b] into [a, b], then for some x ε [a , b], we have f (x)= x.

(ix) If f is continuous in domain D, then 1/f is also continuous in D – {x : f(x)= 0}.

(x) A function f(x) is said to be everywhere continuous, if it is continuous on the entire real line (-∞,∞)

NOW WE WILL DISCUSS DIFFERENTIABILITY AND RELATED RULES:

.

Differentiability in an Interval A function f(x) is said to be differentiable in an interval (a, b), if f(x) is differentiable at every point of this interval (a, b).

A function f(x) is said to be differentiable in a closed interval [a, b], if f(x) is differentiable in (a, b), in addition f(x) is differentiable at x = a from right hand limit and differentiable at x = b from left hand limit.

Relation between Continuity and Differentiability (i) If a function f(x) is differentiable at x = a, then f(x) is necessarily continuous at x = a but the converse is not necessary true.

(ii) The sum, difference, product and quotient of two differentiable function is differentiable. The composition of differentiable function is a differentiable funciton converse of (i) is not necessarily true i.e., if a function f(x) is continuous at x = a, then it is not necessarily differentiable at x = a e.g., f(x) =I xl is continuous at x = 0 but not differentiable at x = 0.

SOME QUESTIONS ARE SOLVED BELOW:

TRY TO SOLVE EXAMPLES GIVEN IN YOUR NCERT TEXT BOOK .LEARN THE ABOVE THEORY AND

FORMULAE PROPERLY.

MD SR. SEC. SCHOOL

GURUGRAM

HOME WORK

CLASS-XII

SUBJECT-PHYSICS

TOPIC-MAGNETISM DATE-16 APRIL2020

READ THE FOLLOWING AND MAKE NOTES:

Torque experienced by a current loop in a uniform

magnetic field

Let us consider a rectangular loop PQRS of length l and breadth b (Fig 3.24).

It carries a current of I along PQRS. The loop is placed in a uniform magnetic field

of induction B. Let θ be the angle between the normal to the plane of the loop and

the direction of the magnetic field.

Magnitude of the force F4 = BIl sin 90o = BIl

F4 acts perpendicular to the plane of the paper and inwards.

The forces F3 and F4 are equal in magnitude, opposite in direction and have

different lines of action. So, they constitute a couple.

Hence, Torque = BIl × PN = BIl × PS × sin θ (Fig 3.25)

= BIl × b sin θ = BIA sin θ

If the coil contains n turns, τ = nBIA sin θ

So, the torque is maximum when the coil is parallel to the magnetic field and

zero when the coil is perpendicular to the magnetic field

OR

Torque on rectangular coil in a magnetic field

As the current carrying conductor experiences a force when placed in a magnetic

field, each side of a current carrying rectangular coil experiences a force in a magnetic

field. In the present section we shall see in what way the rectangular loop carrying

current is influenced by a magnetic field.

Consider a rectangular coil of length l and breadth b carrying a current I placed in a

uniform magnetic field B. θ be the angle between plane of rectangular coil and magnetic field. The magnitude of experienced by each side of loop is given below.

Force acting on side PQ (F1):

the direction of force is perpendicular to the plane containing PQ and B. It is

directed outward direction as shown in figure.

Force acting on side QR (F2):

the direction of force is perpendicular to the plane containing QR and B. It is

directed downward direction as shown in figure.

Force acting on side RS (F3):

the direction of force is perpendicular to the plane containing RS and B. It is

directed inward direction as shown in figure.

Force acting on side SP (F4):

the direction of force is perpendicular to the plane containing SP and B. It is

directed upward direction as shown in figure.

As the force acting on the upper and lower sides are equal and opposite along the

same line of action, they cancel each other. As the force acting on the sides QR and

SP are equal and opposite along different lines of action they constitute a couple.

Hence the rectangular coil experiences a torque.

Therefore the magnitude of torque acting on the coil is

If the rectangular coil having N number of turns then torque is given by

Thus the torque acting on a coil in a magnetic field

depends on the number of turns, area of current loop, strength of current and magnetic

field.

Moving coil Galvanometer

Moving coil galvanometer is a device used for detecting the current in a

circuit.

Principle

Moving coil galvanometer works on the principle that a current carrying coil

placed in a magnetic field experiences a torque.

Construction

It consists of a rectangular coil of a large number of turns of thin insulated

copper wire wound over a light metallic frame (Fig 3.26). The coil is suspended

between the pole pieces of a horse-shoe magnet by a fine phosphor – bronze

strip from a movable torsion head. The lower end of the coil is connected to a hair

spring (HS) of phosphor bronze having only a few turns. The other end of the

spring is connected to a binding screw. A soft iron cylinder is placed symmetrically

inside the coil. The hemispherical magnetic poles produce a radial magnetic field

in which the plane of the coil is parallel to the magnetic field in all its

positions (Fig 3.27).

A small plane mirror (m) attached to the suspension wire is used along with a

lamp and scale arrangement to measure the deflection of the coil.

Let PQRS be a single turn of the coil (Fig 3.28). A current I flows through the

coil. In a radial magnetic field, the plane of the coil is always parallel to the

magnetic field. Hence the sides QR and SP are always parallel to the field. So, they

do not experience any force. The sides PQ and RS are always perpendicular to the

field.

PQ = RS = l, length of the coil and PS = QR = b, breadth of the coil

Force on PQ, F = BI (PQ) = BIl. According to Fleming’s left hand rule, this force

is normal to the plane of the coil and acts outwards.

Force on RS, F = BI (RS) = BIl.

This force is normal to the plane of the coil and acts inwards. These two

equal, oppositely directed parallel forces having different lines of action

constitute a couple and deflect the coil. If there are n turns in the coil,

moment of the deflecting couple = n BIl × b (Fig 3.29)

moment of the deflecting couple = nBIA

When the coil deflects, the suspension wire is twisted. On account of

elasticity, a restoring couple is set up in the wire. This couple is proportional to

the twist. If θ is the angular twist, then,

moment of the restoring couple = Cθ

where C is the restoring couple per unit twist

At equilibrium, deflecting couple = restoring couple nBIA = Cθ

i.e I α θ. Since the deflection is directly proportional to the current flowing

through the coil, the scale is linear and is calibrated to give directly the value of

the current.

2. Pointer type moving coil galvanometer

The suspended coil galvanometers are very sensitive. They can measure

current of the order of 10-8 ampere. Hence these galvanometers have to be

carefully handled. So, in the laboratory, for experiments like Wheatstone’s bridge,

where sensitivity is not required, pointer type galvanometers are used. In this

type of galvanometer, the coil is pivoted on ball bearings. A lighter aluminium

pointer attached to the coil moves over a scale when current is passed. The

restoring couple is provided by a spring.

3. Current sensitivity of a galvanometer.

The current sensitivity of a galvanometer is defined as the deflection

produced when unit current passes through the galvanometer. A galvanometer is

said to be sensitive if it produces large deflection for a small current.

The current sensitivity of a galvanometer can be increased by

1. increasing the number of turns

2. increasing the magnetic induction

3. increasing the area of the coil

4. decreasing the couple per unit twist of the suspension wire. This explains

why phosphor-bronze wire is used as the suspension wire which has small

couple per unit twist.

4. Voltage sensitivity of a galvanometer

The voltage sensitivity of a galvanometer is defined as the deflection per unit

voltage.

where G is the galvanometer resistance.

An interesting point to note is that, increasing the current sensitivity does

not necessarily, increase the voltage sensitivity. When the number of turns (n) is

doubled, current sensitivity is also doubled (equation 1). But increasing the

number of turns correspondingly increases the resistance (G). Hence voltage

sensitivity remains unchanged.

5. Conversion of galvanometer into an ammeter

A galvanometer is a device used to detect the flow of current in an electrical

circuit. Eventhough the deflection is directly proportional to the current, the

galvanometer scale is not marked in ampere. Being a very sensitive instrument, a

large current cannot be passed through the galvanometer, as it may damage the

coil. However, a galvanometer is converted into an ammeter by connecting a low

resistance in parallel with it. As a result, when large current flows in a circuit, only

a small fraction of the current passes through the galvanometer and the

remaining larger portion of the current passes through the low resistance. The

low resistance connected in parallel with the galvanometer is called shunt

resistance. The scale is marked in ampere.

The value of shunt resistance depends on the fraction of the total current

required to be passed through the galvanometer. Let Ig be the maximum current

that can be passed through the galvanometer. The current Ig will give full scale

deflection in the galvanometer.

Galvanometer resistance = G

Shunt resistance = S

Current in the circuit = I

∴ Current through the shunt resistance = Is = (I–Ig)

Since the galvanometer and shunt resistance are parallel, potential is

common.

The shunt resistance is very small because Ig is only a fraction of I.

The effective resistance of the ammeter Ra is (G in parallel with S)

Ra is very low and this explains why an ammeter should be connected in

series. When connected in series, the ammeter does not appreciably change the

resistance and current in the circuit. Hence an ideal ammeter is one which has

zero resistance.

6. Conversion of galvanometer into a voltmeter Voltmeter is an instrument used to measure potential difference between the

two ends of a current carrying conductor.

A galvanometer can be converted into a voltmeter by connecting a high

resistance in series with it. The scale is calibrated in volt. The value of the

resistance

connected in series decides the range of the voltmeter. Galvanometer resistance

= G

The current required to produce full scale deflection in the galvanometer = Ig

Range of voltmeter = V

Resistance to be connected in series = R

Since R is connected in series with the galvanometer, the current through the

galvanometer,

From the equation the resistance to be connected in series with the

galvanometer is calculated.

The effective resistance of the voltmeter is

Rv = G + R

Rv is very large, and hence a voltmeter is connected in parallel in a circuit as it

draws the least current from the circuit. In other words, the resistance of the

voltmeter should be very large compared to the resistance across which the

voltmeter is connected to measure the potential difference. Otherwise, the

voltmeter will draw a large current from the circuit and hence the current through

the remaining part of the circuit decreases. In such a case the potential difference

measured by the voltmeter is very much less than the actual potential difference.

The error is eliminated only when the voltmeter has a high resistance. An ideal

voltmeter is one which has infinite resistance.

कक्षा 12 हहिंदी गृहकार्य 15 अपै्रल ददए गए पत्रों को लललिए एविं काव्य ििंड बात सीधी थी पर प्रश्न र्ाद करने में कोई कमी रह गई हो तो पारार्ण करें

-

HOME WORK

SUBJECT-ENGLISH

DATED-16-04-2020 CLASS-XII