MergedFile - THE SHADI SHOOTSscore-in-chemistry.weebly.com/.../dhs_2014_prelim.pdfPaper 1 Multiple Choice 9646/01 September 2014 1 hour 15 minutes Additional Materials: Multiple Choice

© DHS 2014 9646/Prelim/01/14 [Turn over

DUNMAN HIGH SCHOOL Preliminary Examinations Year 6 Higher 2

PHYSICS Paper 1 Multiple Choice

9646/01

September 2014

1 hour 15 minutes

Additional Materials: Multiple Choice Answer Sheet

READ THESE INSTRUCTIONS FIRST

Write in soft pencil.

Do not use staples, paper clips, highlighters, glue or correction fluid.

Write your name, class and index number on the Answer Sheet in the spaces provided unless this has been

done for you.

DO NOT WRITE IN ANY BARCODES.

There are forty questions on this paper. Answer all questions. For each question there are four possible

answers A, B, C and D.

Choose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet.

Read the instructions on the Answer Sheet very carefully.

Each correct answer will score one mark. A mark will not be ducted for a wrong answer.

Any rough working should be done in this booklet.

The use of an approved scientific calculator is expected, where appropriate.

This document consists of 20 printed pages and 0 blank page.

CANDIDATE NAME

CLASS INDEX NUMBER

2

© DHS 2014 9646/Prelim/01/14

Data

speed of light in free space, c = 3.00 108 m s

-1

permeability of free space, = 4 10-7

H m-1

permittivity of free space, = 8.85 10-12

F m-1

= (1/1(36 )) 10-9

F m-1

elementary charge, e = 1.60 10-19

C

the Planck constant, h = 6.63 10-34

J s

unified atomic mass constant, u = 1.66 10-27

kg

rest mass of electron, = 9.11 10-31

kg

rest mass of proton, = 1.67 10-27

kg

molar gas constant, R = 8.31 J K-1

mol-1

the Avogadro constant, = 6.02 1023

mol-1

the Boltzmann constant, k = 1.38 10-23

J K-1

gravitational constant, G = 6.67 10-11

N m2

kg-2

acceleration of free fall, g = 9.81 m s-2

3


Formulae

uniformly accelerated motion, s = ut +

at

2

v 2 = u

2 + 2as

work done on/by a gas, 0B0B0B0B0B0B0B0B0B0BW = p V

hydrostatic pressure, 1B1B1B1B1B1B1B1B1B1Bp = gh

gravitational potential, =

displacement of particle in s.h.m., x = x0 sin t

velocity of particle in s.h.m., v = v0 cos t

v = √ -

mean kinetic energy of a molecule

of an ideal gas E =

3

2kT

resistors in series, R = …

resistors in parallel, 1/R = 1/ + 1/ + ...

electric potential, V =

alternating current/voltage, x = x0 sin t

transmission coefficient, T exp( 2kd)

where k = √ ( )

radioactive decay, x = exp( t)

decay constant, =

4

© DHS 2014 9646/Prelim/01/14

1 Which quantity has different units from the other three?

A rate of change of momentum

B gradient of electric potential energy

C impulse per unit time

D power over displacement

2 The Lyman series is the series of transitions resulting in ultraviolet emission lines of hydrogen

atom as an electron goes from higher energy levels to ground state. It is given by the formula

2

11

1

nR

H

where n is a natural number greater than or equal to 2.

A student conducted an experiment to determine the constant RH. The results are summarized

below:

n wavelength λ (nm)

2 122 2

What is the average value for RH and its corresponding uncertainty?

A (1.093 0.009) 107 m 1 B (1.09 0.02) 107 m 1

C (1.09 0.04) 107 m 1 D (1.1 0.1) 107 m 1

5


3 body falls from r st in a vacuum n ar th Earth’s surfac Th variation with tim t of its

speed v is shown below.

Which graph shows the variation with time t of the speed v of the same ball falling in air at the

same place on Earth?

A B

C D

4 A force F is applied to a freely moving object. At one instant of time, the object has velocity v

and acceleration a.

Which quantities must be in the same direction?

A a and v only

B a and F only

C v and F only

D v, F and a

v

t 0

v

t 0

v

t 0

v

t 0

v

t 0

6

© DHS 2014 9646/Prelim/01/14

5 What is meant by the weight of an object?

A the gravitational field acting on the object

B the gravitational force acting on the object

C the mass of the object multiplied by gravity

D th obj ct’s mass multi li d by its acc l ration

6 Two spheres A and B approach each other along the same straight line with speed uA and

speed uB. The spheres collide and move off with speeds vA and vB, both in the same direction

as the initial direction of sphere A, as shown below.

Which equation applies to an elastic collision?

A uA + uB = vB – vA

B uA – uB = vB – vA

C uA – uB = vB + vA

D uA + uB = vB + vA

7 A uniform metre ruler of mass 100 g freely rotates around a pivot at the 40 cm mark. At the

100 cm mark, a string is secured and passed round a frictionless pulley, carrying a mass of

20 g as shown in the diagram.

At which mark on the ruler must a 50 g mass be suspended so that the ruler balances?

A 4 cm B 36 cm C 44 cm D 96 cm

before collision

after collision

uA

vA

uB

vB

A B

20 g

0 20 40 60 80 100

7


8 The graph shows the variation with time of the momentum of a ball as it is kicked in a straight

line.

Initially, the momentum is p1 at time t1. At time t2 the momentum is p2.

What is the magnitude of the average force acting on the ball between times t1 and t2?

A -

B

-

- C

D

-

9 The diagram shows two identical vessels X and Y connected by a short pipe with a tap.

Initially, X is filled with water of mass m to a depth h, and Y is empty. When the tap is opened,

water flows from X to Y until the depths of water in both vessels are equal.

How much potential energy is lost by the water during this process? (g = acceleration of free fall)

A 0 B

C

D mgh

momentum

time

p1

p2

0 0

t1 t2

h

X Y

m

8

© DHS 2014 9646/Prelim/01/14

10 A boy on a boat X pulls on a rope with a constant force F over a duration of time t. The other

end of the rope is either tied to an anchor on (a) the pier or (b) a freely floating boat Y of equal

mass as shown below.

Wa and Wb are the total work done by the boy during the time t whereas Pa and Pb are the

average power output by the boy for case (a) and (b) respectively.

Which of the following is correct?

A Wa > Wb and Pa > Pb B Wa = Wb and Pa = Pb

C Wa < Wb and Pa < Pb D Wa > Wb and Pa = Pb

11 A light pail containing water is attached to a light rope and swung around in a vertical circle.

The radius of the circular motion is 1.0 m. The water just manages to stay in the pail at the

highest point of motion.

What is the linear speed of the pail at the lowest point of motion?

A 3.13 m s-1 B 5.42 m s

-1 C 7.00 m s-1 D 7.87 m s

-1

(a)

anchor

(b)

X

X Y

1.0 m

9


12 A ball of mass 1.5 kg is attached to a light string of length 2.0 m and made to rotate in a

horizontal circle.

The string snaps when the linear speed of the ball reaches 12.0 m s-1.

What is the maximum tension the string is able to withstand?

A 18.9 N B 110 N C 217 N D 277 N

13 G ostationary sat llit s r main abov fix d oints on th Earth’s surfac along the equator as

the Earth rotates about its axis. They orbit with a fixed radius of rgeo around the Earth, which

has a radius of RE.

In comparison, polar-orbiting satellites pass above the North and South poles of the Earth on

each revolution. A polar orbit is illustrated in the figure above.

What will be the ratio an ular v locity of olar-orbitin sat llit

an ular v locity of ostationary sat llit if the polar orbit is 16 times lower

in altitude as that of a geostationary orbit?

A 4 B 4 (

- E o

)

C 64 D 64 (

E o

)

2.0 m

1.5 kg

equator

Earth

polar orbit

RE

rgeo

10

© DHS 2014 9646/Prelim/01/14

14 A satellite of mass 50 kg moves from a point where the gravitational potential due to the Earth

is -20 MJ kg-1, to another point where the gravitational potential is -60 MJ kg

-1.

In which direction does the satellite move and what is its change in potential energy?

A closer to the Earth and a loss of 2000 MJ of potential energy.

B closer to the Earth and a loss of 40 MJ of potential energy.

C further from the Earth and a gain of 2000 MJ of potential energy.

D further from the Earth and a gain of 40 MJ of potential energy.

15 The diagram shows the graph of velocity against time for a body performing simple harmonic

motion.

At which point are the velocity and acceleration in opposite directions?

16 The diagram below shows 3 identical springs arranged in different manners.

Which arrangement will result in vertical oscillations of the highest frequency?

A B C D

17 A cup contains 300 g of freshly brewed tea at 93°C. It cools at an average rate of 60 W and the

heat capacity of tea is 1250 J K 1.The tea is best consumed before it cools below 45°C.

What is the maximum amount of time a student has to enjoy his cup of freshly brewed tea?

A 300 s B 1000 s C 3300 s D 3600 s

time

velocity

A

B

0

C D

m

m

m m

11


18 Which statement about internal energy of an ideal gas is correct?

A It is the sum of kinetic energies due to random motion of gas particles.

B It is the sum of potential energies due to intermolecular attraction of gas particles.

C It is the sum of kinetic energies due to random motion and potential energies due to

intermolecular attraction of gas particles.

D It is the average of kinetic energies due to random motion and potential energies due to

intermolecular attraction of gas particles.

19 Unpolarized light is incident on a polarizer as shown below. The intensity of the light

emerging from the first polarizer is I0. The first polarizer is vertically polarized while the

polarizing axis of the second polarizer is 50° from the vertical.

What is the intensity of light emerging from the second polarizer?

A 0.413 I0 B 0.642 I0 C 0.826 I0 D I0

20 A progressive wave is one which

A has vibrations that are perpendicular to the direction of wave travel.

B has vibrations that are parallel to the direction of wave travel.

C transfers energy in the direction of wave travel.

D transfers energy and particles in the direction of wave travel.

21 The diagram shows a standing wave on a string. The standing wave has three nodes N1, N2

and N3.

Which statement is correct?

A All points on the string vibrate in phase.

B All points on the string vibrate with the same amplitude.

C Points equidistant from N2 vibrate with the same frequency and in phase.

D Points equidistant from N2 vibrate with the same frequency and the same amplitude.

50

I0

N1 N2 N3

12

© DHS 2014 9646/Prelim/01/14

22 A diffraction grating with N lines per metre is used to deflect light of various wavelengths λ.

The diagram shows a relation between the deflection angles of θ for different values of λ in the

nth order interference pattern.

What is the gradient of the graph?

A Nn B

C

D

23 Which of the following statements about an electric field is incorrect?

A The electric field strength at a point is a measure of the potential gradient at that point.

B Electric field strength is a vector quantity.

C The electric field strength at a point is the force per unit positive charge experienced by

a small test charge placed at that point.

D The electric field strength is zero at all points where the potential is zero.

24 A potential difference is applied between two metal plates that are not parallel.

Which diagram shows the electric field between the plates?

A B

C D

sin θ

0 λ

- + - +

- + - +

13


25 The electron beam current in a cathode-ray oscilloscope is 40 A. The time-base of the

oscilloscope is set at 20 ms cm 1.

What is the number of electrons arriving at the screen in two centimetre length of the horizontal

trace?

A 1010 B 1013 C 1016 D 1019

26 A battery of e.m.f. E and internal resistance r delivers a current I through a variable resistance

R.

R is set at two different values and the corresponding currents I are measured using an

ammeter of negligible resistance.

R / I / A

1.0 3.0

2.0 2.0

What is the value of internal resistance r and e.m.f. E?

E / V r / Ω

A 3.0 1.0

B 3.0 2.0

C 6.0 1.0

D 6.0 2.0

R

r E

A

I

14

© DHS 2014 9646/Prelim/01/14

27 Six resistors are connected to a 2 V cell of negligible internal resistance.

What is the potential difference between terminals X and Y?

A 2/3 V B 32/143 V C 64/143 V D 98/143 V

28 In the potentiometer circuit below, the moveable contact is placed at N on the bare wire XY,

such that the galvanometer shows zero deflection.

The resistance of the variable resistor is now increased.

What is the effect of this increase on the potential difference across the wire XY and on the

position of the moveable contact for zero deflection?

potential difference across XY position of moveable contact

A increases nearer to X

B increases nearer to Y

C decreases nearer to X

D decreases nearer to Y

2 V

Ω

Ω

Ω

Ω

Ω

Ω

X

Y

X Y N

15


29 Four particles independently move at the same speed in a direction perpendicular to the same

magnetic field.

Which particle is deflected the most?

A a copper ion

B a helium nucleus

C an electron

D a proton

30 A thin slab of p-type semiconductor is connected at its ends to a battery causing a current

through it.

A uniform magnetic field is applied vertically downwards over the surface of the slab causing an

electric field between sides X and Y of the slab.

Which option correctly describes the majority carriers of the electric current in the slab and the

direction of the induced electric field?

majority carriers electric field direction

A conduction electrons from X to Y

B conduction electrons from Y to X

C holes from X to Y

D holes from Y to X

X

Y

p-type semiconductor

+

-

16

© DHS 2014 9646/Prelim/01/14

31 A small copper disc spins on an axle lie along the centre of a long solenoid. An induced e.m.f.

is generated between the axle and the circumference of the disc.

Which of the following changes does not result in a larger magnitude of induced e.m.f.?

A placing a soft iron core to the left of the disc.

B spinning the axle with a larger angular speed.

C increasing the current in the solenoid.

D cooling the copper disc.

32 An soft-iron ring hangs vertically from a thread and has its axis aligned with a coil.

The current in the coil is switched on at time t0.

Which of the following graphs shows a possible variation of the angular displacement that the

thread makes with the vertical, θ, with time?

A B

C D

disc

solenoid

axle

common axis

coil ring

thread

θ

θ

time t0

θ

time

t0

θ

time

t0

θ

time t0

17


33 The diagram below shows a transformer which allows perfect magnetic flux linkage between

the primary and secondary coil. The primary coil is supplied with an a.c. supply of power P.

There are 4 times as many turns in the secondary coil as in the primary coil. The wires making

up the primary coil are the same type as the secondary coil, and have a total resistance of r,

and the load resistor across the secondary coil has a resistance of R. The r.m.s. current in the

primary and secondary circuits are denoted Ip and Is, respectively.

What is the power dissipated in the load resistor?

A P – Ip2r B P – (Ip

2 + 4Is2)r C P D (

)

34 A signal generator can produce a variety of voltage waveforms. The diagram below shows 2

possible cases, (a) and (b).

What is the ratio m an ow r in cas

m an ow r in cas for a pure resistive load?

A 0.250 B 0.354 C 0.500 D 0.707

~

primary secondary

power P

R r

Ip

Is

4r

e.m.f.

Vp

time

e.m.f.

Vp

time

(a) (b)

18

© DHS 2014 9646/Prelim/01/14

35 When electromagnetic radiation of frequency f falls on a particular metal surface,

photoelectrons may be emitted. The graph below shows the variation with f of the stopping

potential V of these electrons for different materials P, Q and R.

Which of the following statement is correct?

A P has the smallest work function because f is higher for the same V.

B R has the smallest work function because V is higher for the same f.

C P emits the most number of photoelectrons because its work function is the smallest.

D R emits the most number of photoelectrons because its work function is the smallest.

36 The diagram shows the emission spectrum of a gas. The frequency scale is linear and

increases to the right.

Which diagram best illustrates the transition in energy levels of the gas atoms?

A B

C D

19


37 The diagram below shows the energy levels for the atoms of a 4-level laser system.

Which set of life-times for electrons residing in that energy state is possible if E2 is the

metastable state for this laser system?

E1 E2 E3

A 10-3 s 10-8 s 10-7 s

B 10-7 s 10-9 s 10-3 s

C 10-7 s 10-3 s 10-9 s

D 10-8 s 10-3 s 10-2 s

38 Which diagram illustrates the valence band vb, the conduction band cb, and the dopant level d

in an intrinsic semiconductor doped with electron-deficient impurity atoms that is at zero kelvin?

A B

C D

energy

Eground

E1

E2

E3

cb

d

vb

cb

d

vb

cb

d

vb

cb

d

vb

20

© DHS 2014 9646/Prelim/01/14

39 A graph of the natural logarithm of the activity A of a radioactive source plotted against time is

given.

What is the half-life of the source in years?

A 99 B 186 C 300 D 517

40 In an -particle scattering experiment, a student determined the number n of -particles

incident per unit time on a detector held at various angular positions .

Which graph best represents the variation of n with θ?

A B

C D

ln (A / Bq)

time / year

7.6

3.4

0 600

thin gold foil

detector +90°

-90°

-170°

+170° θ

0° α-particles

0

n

+90 -90 -170 +170 θ/° 0

n

+90 -90 -170 +170 θ/°

0

n

+90 -90 -170 +170 θ/° 0

n

+90 -90 -170 +170 θ/°



PHYSICS Paper 2 Structured Questions Candidates answer on the Question Paper.

No Additional Materials are required.

9646/02

September 2014

1 hour 45 minutes


Write your class, index number and name on all the work you hand in.

Write in dark blue or black pen on both sides of the paper.

You may use a soft pencil for any diagrams, graphs or rough working.




Answer all questions.

At the end of the examination, fasten all your work securely together.

The number of marks is given in brackets [ ] at the end of each question or part

question.

For Examiner’s Use

1 8

2 8

3 8

4 8

5 13

6 15

7 12

Total 72


CANDIDATE NAME

CLASS INDEX NUMBER

2

© DHS 2014 9646/Prelim/02/14

Data


-1


H m-1


F m-1

= (1/1(36 )) 10-9

F m-1


C


J s


kg


kg


kg


mol-1


mol-1


J K-1


N m2

kg-2


3

© DHS 2014

9646/Prelim/02/14 [Turn over

Formulae


at

2

v 2 = u

2 + 2as

work done on/by a gas, 0B0B0B0B0B0BW = p V

hydrostatic pressure, 1B1B1B1B1B1Bp = gh




v = √ -


of an ideal gas E =

3

2kT






where k = √ ( )


decay constant, =

4

© DHS 2014 9646/Prelim/02/14

For Examiner’s

Use

1 Trolley A of mass 400 g is moving at a constant speed of 2.5 m s-1 to the right as shown in

Fig. 1.1.

(a) Show that the kinetic energy of trolley A is 1.3 J.

[1]

Trolley A hits a spring of force constant k = 20 N m-1 and compresses the spring from its

equilibrium position before coming to rest momentarily.

(b) (i) Define elastic potential energy.

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [ ]

(ii) Calculate the maximum compression of the spring.

compression = ……………………………… m [2]

(iii) The length of the spring is then cut in half. Trolley A is, again, travelling with speed

of 2.5 m s-1 and hits the spring.

Suggest and explain the change, if any, on the maximum compression of the

spring.

… … …………………………………………………………………………………………

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [ ]

400 g

2.5 m s-1

trolley A

Fig. 1.1

5

© DHS 2014


For Examiner’s

Use

(c) Two identical trolleys, A and B, start from rest at the same height above the ground and

travel to the right on two frictionless tracks as shown in Fig. 1.2.

State and explain which trolley will reach the finish line first.

… … ……………………………………………………………………………………………

… … ……………………………………………………………………………………………

…………………… ………………………………………………………………………… [ ]

trolley B

finish line

trolley A

frictionless tracks

Fig. 1.2

6

© DHS 2014 9646/Prelim/02/14

For Examiner’s

Use

2 (a) State two necessary conditions that must be satisfied in order that coherent waves may

interfere.

: … ……………………………………………………………………………………………

… … ……………………………………………………………………………………………

: … ……………………………………………………………………………………………

…………………… ………………………………………………………………………… [ ]

(b) Light from a light source is incident on a double slit after passing through a single slit, as

shown in Fig. 2.1. Interference fringes are observed on the screen.

(i) Explain why a single slit is used in the apparatus.

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [ ]

(ii) The intensity at B due to each wave is I. Determine, in terms of I, the resultant

intensity of the waves at B.

resultant intensity = ……………………………… I [2]

(iii) State the phase difference between the waves that meet at P.

phase difference = ……………………………… [1]

C bright fringe

P dark fringe

B bright fringe

double slit single slit

light source

screen

s1

s2

Fig. 2.1 (not to scale)

7

© DHS 2014


For Examiner’s

Use

(iv) A third slit s3 is now made at an equal distance below s2, as shown in Fig. 2.2.

Explain if point P on the screen remains dark.

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [ ]

C

P

B light

source

screen

s1

s2


s3

8

© DHS 2014 9646/Prelim/02/14

For Examiner’s

Use

3 (a) Two long, straight, current-carrying conductors, PQ and XY, are held a constant

distance apart, as shown in Fig. 3.1.

The conductors each carry the same magnitude of current in the same direction.

A plan view from above the conductors is shown in Fig. 3.2.

(i) On Fig. 3.2 draw arrows, one in each case, to show the direction of:

1. the magnetic field at Q due to the current in wire XY (label this arrow B). [1]

2. the force at Q as a result of the magnetic field due to the current in wire XY

(label this arrow F). [1]

(ii) Conductor PQ is free to move.

Describe and explain the subsequent motion of the conductor PQ.

… … …………………………………………………………………………………………

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [ ]

I I

Q

P

Y

X Fig. 3.1

Q Y

Fig. 3.2

9

© DHS 2014


For Examiner’s

Use

(b) Conductor PQ is now placed horizontally as shown in Fig. 3.3. Above PQ is another

conductor CD that can slide up and down on two vertical metal rods while making

electrical contact with them.

When switch S is closed such that current flows in CD, CD moves upwards and

eventually comes to rest at a certain height above PQ.

(i) Explain why CD initially starts to move upwards.

… … …………………………………………………………………………………………

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [ ]

(ii) Explain why CD eventually comes to rest at a certain height above PQ.

… … …………………………………………………………………………………………

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [ ]

Q P

D C

S

Fig. 3.3

I

10

© DHS 2014 9646/Prelim/02/14

For Examiner’s

Use

4 Some electron energy levels in atomic hydrogen are illustrated in Fig 4.1.

(a) Two possible electron transitions A and B giving rise to an emission spectrum are

shown. These electron transitions cause light of wavelengths 654 nm and 488 nm to be

emitted.

(i) On Fig 4.1, draw an arrow to show a third possible transition. [1]

(ii) Calculate the wavelength of the emitted light for the transition in part (i).

wavelength = ……………………………… m [3]

(b) White light in a beam is incident on some cool hydrogen gas as shown in Fig. 4.2.

Using the values of wavelength in (a), state and explain the appearance of the spectrum

of the emergent light.

… … ……………………………………………………………………………………………

… … ……………………………………………………………………………………………

… … ……………………………………………………………………………………………

…………………… ………………………………………………………………………… [ ]

0.85 eV

1.50 eV

3.40 eV

energy

A B

Fig. 4.1

cool hydrogen gas incident

light emergent

light

Fig. 4.2

11

© DHS 2014


For Examiner’s

Use

5 The variation of electrical resistance of a thermistor with temperature is shown in Fig. 5.1.

(a) Thermistors can be made with intrinsic semiconductor materials.

Describe how band theory is used to explain the trend of the graph shown in Fig. 5.1.

… … ……………………………………………………………………………………………

… … ……………………………………………………………………………………………

… … ……………………………………………………………………………………………

… … ……………………………………………………………………………………………

… … ……………………………………………………………………………………………

… … ……………………………………………………………………………………………

… … ……………………………………………………………………………………………

…………………… ………………………………………………………………………… [ ]

resistance

/ Ω

temperature / °C

22

14

24

20

16

18

12 14 16 18 20 22 24

Fig. 5.1

12

© DHS 2014 9646/Prelim/02/14

For Examiner’s

Use

(b) Fig. 5.2 shows a circuit which can be used to determine the temperature of the

thermistor with the help of Fig. 5.1. A uniform metre wire AB is connected between the

terminals of a driver cell of e.m.f. 3.0 V and of negligible internal resistance.

(i) State the ratio of the potential differences across AJ and HF at balance length.

ratio = ……………………………… [1]

(ii) Explain whether the temperature measurement is more or less accurate when the

internal resistance of battery E is large.

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [ ]

(iii) The galvanometer shows zero deflection when length AJ is 0.40 m.

Determine the potential difference across HF.

potential difference = ……………………………… V [1]

G

A B

C

D

H F

J

r

3.0 V

Fig. 5.2

E

A

13

© DHS 2014


For Examiner’s

Use

(iv) Given that the temperature of the thermistor is 24.0°C at balance length conditions,

1. state the resistance of the thermistor,

resistance = ……………………………… Ω [ ]

2. determine the current flowing through battery E.

current = ……………………………… A [1]

3. Circuit DCHF is at a situation where there is maximum power being

transferred from the battery to the thermistor.

Calculate the e.m.f. of battery.

e.m.f. = ……………………………… V [2]

(v) Determine the balance length when the semiconductor-based thermistor is at 0 K.

Explain your working.

balance length = ……………………………… m [2]

14

© DHS 2014 9646/Prelim/02/14

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Use

6 Pitot-static tubes are used on aircraft as speedometers. The Pitot-static tube is mounted on

the aircraft so that the centre tube is always pointed in the direction of travel and the outside

holes are perpendicular to the centre tube.

A schematic Pitot-static tube is shown in Fig. 6.1. The outside holes are at normal air

pressure, otherwise known as the static pressure PS. The centre tube is pointed in the

direction of travel. The pressure in the centre tube is known as the total pressure PT, and it

increases with the velocity of the aircraft.

The difference in total and static pressure is the dynamic pressure q,

q = PT – PS

(a) State and explain whether the Pitot-static tube will give a more accurate reading at high

or low aircraft velocities.

… … ……………………………………………………………………………………………

…………………… ………………………………………………………………………… [ ]

(b) It is thought that dynamic pressure obeys a relation of the form

q =

ρvn

where n is a constant and ρ is the local value of air density.

Explain how the relation may be tested by plotting a graph of lg q on the y-axis against

lg v on the x-axis.

… … ……………………………………………………………………………………………

… … ……………………………………………………………………………………………

… … ……………………………………………………………………………………………

…………………… ………………………………………………………………………… [ ]

air velocity v

centre tube

outside holes

Pitot-static tube

Fig. 6.1

15

© DHS 2014


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Use

(c) Fig. 6.2 shows the values of dynamic pressure q, measured by a Pitot-static tube when

an aircraft is moving with velocity v.

v / m s-1 q / N m

-2 lg (v / m s-1) lg (q / N m

-2)

80 2902 1.90 3.463

90 3689 1.95 3.567

100 4470 2.00 ………………

110 5507 2.04 3.741

120 6408 2.08 3.807

Fig. 6.2

(i) Complete Fig. 6.2 for the velocity v of 100 m s-1. [1]

(ii) Fig. 6.3 is a graph of some of the data in Fig. 6.2.

lg (q / N m-2

)

lg (v / m s-1

)

1.90 1.94 1.98 2.02 2.06 2.10 3.40

3.50

3.60

3.70

3.80

3.90

4.00

Fig. 6.3

16

© DHS 2014 9646/Prelim/02/14

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Use

On Fig. 6.3,

1. plot the point corresponding to v = 100 m s-1, [1]

2. draw the line of best fit for the points. [1]

(iii) Use the line drawn in part (c)(ii) to determine the magnitudes of the constant n and

the air density ρ in the expression given in part (b).

n = ……………………………… [2]

ρ = ……………………………… kg m-3 [2]

(d) A blocked Pitot-static tube is a problem that will affect airspeed indicator.

(i) Explain how a blocked centre tube with constant PT can register a lower airspeed

when the aircraft descends, even though actual airspeed is constant.

… … …………………………………………………………………………………………

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [ ]

(ii) Suggest what could possibly cause the blockage of the centre tube.

… ………………………………………………………………………………………… [ ]

17

© DHS 2014


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Use

7 An aluminium ring is placed on a coil with the rod of a metal retort stand passing through

their centres, as shown in Fig. 7.1.

Fig. 7.1

When an alternating current of frequency f is applied to the coil, the ring rises until it is in

equilibrium at height h above the coil.

It is suggested that the relationship between h and f is

nkfh

where k and n are constants.

Design a laboratory experiment to test the relationship between h and f and determine

values for k and n. You should draw a diagram showing the arrangement of your equipment.

In your account you should pay particular attention to

(a) the procedure to be followed,

(b) the measurements to be taken,

(c) the control of variables,

(d) the analysis of the data,

(e) the safety precautions to be taken.

aluminium ring with zero current applied to coil

metal retort stand

coil

h

aluminium ring when alternating current applied to coil

18

© DHS 2014 9646/Prelim/02/14

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Diagram

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19

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20

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PHYSICS Paper 3 Longer Structured Questions Candidates answer on the Question Paper.

No Additional Materials are required.

9646/03

25 September 2014

2 hours


Write your class, index number and name on all the work you hand in.

Write in dark blue or black pen on both sides of the paper.

You may use a soft pencil for any diagrams, graphs or rough working.




Section A

Answer all questions.

Section B

Answer any two questions.

You are advised to spend about one hour on each section

At the end of the examination, fasten all your work securely together.

The number of marks is given in brackets [ ] at the end of each question

or part question.

For Examiner’s Use

Section A

1 8

2 8

3 6

4 8

5 10

Section B

6 20

7 20

8 20

Total 80


CANDIDATE NAME

CLASS INDEX NUMBER

2

© DHS 2014 9646/Prelim/03/14

Data


-1


H m-1


F m-1

= (1/1(36 )) 10-9

F m-1


C


J s


kg


kg


kg


mol-1


mol-1


J K-1


N m2

kg-2


3

© DHS 2014


Formulae


at

2

v 2 = u

2 + 2as

work done on/by a gas, 0B0B0B0B0B0B0B0B0B0B0B0B0BW = p V

hydrostatic pressure, 1B1B1B1B1B1B1B1B1B1B1B1B1Bp = gh




v = √ -


of an ideal gas E =

3

2kT






where k = √ ( )


decay constant, =

4

© DHS 2014 9646/Prelim/03/14

For Examiner’s

Use

Section A

Answer all the questions in the spaces provided.

1 The arrangement shown in Fig. 1.1 is used to determine the length x of a spring when

different masses M are attached to the spring.

The variation with length x of mass M is shown in Fig. 1.2.

(a) State the natural length of the spring.

natural length = ……………………………… m [1]

(b) Use Fig. 1.2 to determine the spring constant of the spring.

spring constant = ……………………………… N m-1 [2]

spring

mass

Fig. 1.1

x

x / cm

M / kg

70 65 60 55 50 45 75 0

0.20

0.40

0.60

Fig. 1.2

5

© DHS 2014


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Use

A mass m is then attached to the spring. The mass is displaced vertically then released.

The variation with time t of the displacement y from its mean position is shown in Fig. 1.3.

(c) Calculate the angular frequency of the oscillation.

angular frequency = ……………………………… rad s-1 [1]

(d) The spring-mass system undergoes free oscillations.

(i) Explain what is meant by free oscillations.

… ………………………………………………………………………………………… [ ]

(ii) Determine the mass m that results in the oscillations shown in Fig. 1.3.

m = ……………………………… kg [2]

(iii) Hence or otherwise, find the length x of the spring at y = 0 cm.

x = ……………………………… m [1]

Fig. 1.3

y / cm

0 t / s 0.25 0.50 0.75 1.00 1.25

1.50 0

6

© DHS 2014 9646/Prelim/03/14

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Use

2 The variation with time t of the displacement x of a point in a transverse wave T1 is shown

in Fig. 2.1.

(a) By reference to displacement and direction of travel of wave energy, explain what is

meant by a transverse wave.

… … ……………………………………………………………………………………………

…………………… ………………………………………………………………………… [ ]

(b) A second transverse wave T2 of amplitude A has the same waveform as wave T1 but

leads T1 by a phase angle of

. The two waves T1 and T2 pass through the same point.

(i) On Fig. 2.1, draw the variation with time t of the displacement x of the point in

wave T2. [2]

(ii) Explain what is meant by the principle of superposition of the two waves.

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [2]

(iii) For the time t = 1.0 s, use Fig. 2.1 to determine, in terms of A,

1. the displacement due to wave T1 alone,

displacement = ……………………………… [1]

2. the displacement due to wave T2 alone,

displacement = ……………………………… [1]

3. the resultant displacement due to both waves.

displacement = ……………………………… [1]

Fig. 2.1

7

© DHS 2014


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Use

3 (a) Stat Faraday’s law of l ctromagn tic induction

… … ……………………………………………………………………………………………

… … ……………………………………………………………………………………………

…………………… ………………………………………………………………………… [ ]

(b) Fig. 3.1 shows a solid metal cylinder with an empty axial core portion rotating in a

region of uniform magnetic field.

(i) Explain why the voltmeter in Fig. 3.1 indicates a non-zero reading.

… ……………………………………………………………………………………………

.. ……………………………………………………………………………………………

.. ……………………………………………………………………………………………

… … ………… ………………………………………………………………………… [2]

Fig. 3.1

N S V

8

© DHS 2014 9646/Prelim/03/14

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Use

(ii) Explain why, in the absence of external forces and friction, the rotation of the solid

metal cylinder eventually stops.

……………………………………………………………………………………………

……………………………………………………………………………………………

……………………………………………………………………………………………

……………………………………………………………………………………………

……………………………………………………………………………………………

……………… ………………………………………………………………………… [3]

9

© DHS 2014


For Examiner’s

Use

4 A beam of electrons is directed at right-angles to a barrier in a vacuum, as shown in Fig. 4.1.

The barrier contains a single slit of width w. Beyond the slit there is a detector that counts

electrons. The detector can be moved in the y-direction to count the rate of arrival of

electrons at different values of the angle θ from the original direction of the beam.

H is nb rg’s unc rtainty rinci l can be used to explain why the electron beam spreads

out after passing through the slit. It can be represented by the equation:

(a) Identify the terms below and explain how the terms apply to the electrons as they pass

through the slit.

(i) y

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [2]

(ii) p

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [2]

(b) Hence use the uncertainty principle to explain why

(i) the beam spreads out,

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [2]

(ii) the beam is spread out more when the slit is narrower (smaller w).

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [2]

electron beam

barrier

w

θ

y-direction

electron counter

Fig. 4.1

10

© DHS 2014 9646/Prelim/03/14

For Examiner’s

Use

5 One of the heaviest elements synthesized in the laboratory is Livermorium. It was created by

bombarding stationary Curium-248 atoms with Calcium-48 atoms. The reaction is

represented by the equation

m a

n

(a) (i) Determine the value of A and Z in the equation.

A = ……………………………… [0]

Z = ……………………………… [1]

(ii) The binding energy per nucleon of each nucleus is as follows.

m

7.307501 MeV

a

8.464048 MeV

6.917282 MeV

Calculate the energy required to synthesize an atom of livermorium.

energy required = ……………………………… J [2]

(iii) Suggest a reason why the actual amount of energy needed to synthesize an atom

of livermorium is higher than the energy calculated in part (a)(ii).

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [1]

11

© DHS 2014


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Use

(b) Livermorium atoms are extremely unstable and will each quickly undergo three

successive alpha decays to form darmstadtium. Darmstadtium atoms undergo

spontaneous nuclear fission.

(i) Explain what is meant by spontaneous.

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [1]

(ii) In Fig. 5.1, sketch a carefully-labelled graph of the variation with nucleon number of

the binding energy per nucleon of a nucleus.

Mark the approximate positions for the nuclei of calcium-48 (label the position Ca),

curium-248 (label the position Cm) and Livermorium-A (label the position Lv) on

your graph. [3]

(iii) Using your answer to part (b)(ii), explain whether darmstadtium atoms will release

energy when they undergo nuclear fission.

… … …………………………………………………………………………………………

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [2]

binding energy per nucleon

nucleon number

Fig. 5.1

0

12

© DHS 2014 9646/Prelim/03/14

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Use

Section B

Answer two questions from this Section in the spaces provided.

6 (a) Define gravitational field strength.

… … ……………………………………………………………………………………………

…………………… ………………………………………………………………………… [ ]

(b) The mass M of a spherical planet may be assumed to be a point mass at the centre of

the planet.

A stone, travelling at speed v, is in a circular orbit of radius r about the planet, as

illustrated in Fig. 6.1.

Show that the speed v is given by the expression

√(

)

where G is the gravitational constant.

[2]

stone

planet

v

r

Fig. 6.1

13

© DHS 2014


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Use

(c) Define gravitational potential at a point.

… … ……………………………………………………………………………………………

…………………… ………………………………………………………………………… [ ]

(d) Fig. 6.2 shows a second stone, initially at rest at infinity, traveling towards the planet.

The stone does not hit the surface of the planet.

(i) Determine, in terms of the gravitational constant G and the mass M of the planet,

the speed V0 of the stone at a distance x from the centre of the planet. Explain your

working. You may assume that the gravitational attraction on the stone is due only

to the planet.

[3]

(ii) Use your answer in (d)(i) and the expression in (b) to explain whether this stone

could enter a circular orbit about the planet.

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [2]


stone

planet

V0

x

14

© DHS 2014 9646/Prelim/03/14

For Examiner’s

Use

(e) Fig. 6.3 shows a typical weather balloon consisting of a helium-filled lifting bag

connected to a sensor package for measuring atmospheric parameters.

It can reach a maximum height of 40 km above the ground.

(i) Explain why does the lifting bag experiences a net upward force at the ground.

… … …………………………………………………………………………………………

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [2]

(ii) Identify the force(s) acting on the weather balloon and state the relationship

between the magnitudes of the forces when the weather balloon reaches maximum

height.

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [1]

(iii) Given that the radius of Earth, RE, is 6400 km, show that the gravitational field

strength, g, experienced by a weather balloon at maximum height deviates from

that at the ground by 1.2%. Take g at the ground to be 9.81 m s-2.

[2]

Fig. 6.3

cord

lifting bag

sensor package

15

© DHS 2014


For Examiner’s

Use

(iv) The tension in the cord connecting a sensor package to the lifting bag hovering at

maximum height was found to be 2.42 N.

Determine the mass of the sensor package.

mass = ……………………………… kg [1]

(v) The lifting bag bursts at the maximum height. An estimate of the time taken for the

free fall of the sensor package to reach the ground, t, can be made by assuming

that the gravitational field strength remains constant.

1. Determine t using the value of gravitational field strength at the maximum

height.

t = ……………………………… s [2]

2. Explain if your answer for t is an over-estimate or an under-estimate.

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [1]

(f) The lifting bag will burst at a fixed maximum volume.

Explain why increasing the initial volume of the lifting bag at ground level will cause the

bag to burst at a lower maximum height.

… … ……………………………………………………………………………………………

… … ……………………………………………………………………………………………

…………………… ………………………………………………………………………… [2]

16

© DHS 2014 9646/Prelim/03/14

For Examiner’s

Use

7 The volume of 1.00 kg of water at 100°C, under an atmospheric pressure of 1.01 × 105 Pa,

in various states is shown in Fig. 7.1.

state volume / m3

liquid 1.00 × 10-3

vapour 1.69

Fig. 7.1

(a) Show that the work done against the atmosphere when 1.00 kg of liquid water becomes

water vapour is 1.710 × 105 J.

[2]

(b) (i) The first law of thermodynamics may be given by the expression

Q U + w

where Q is the heat supplied to the system.

State what is meant by

1. U

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [1]

2. +w

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [1]

17

© DHS 2014


For Examiner’s

Use

(ii) The specific latent heat of vaporisation of water at 100°C is 2.26 × 106 J kg-1.

A mass of 2.50 kg of liquid water becomes water vapour at 100°C.

1. State what is meant by specific latent heat of vaporisation.

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [1]

2. Determine, using your answer in (a), the increase in internal energy of this

mass of water during vaporisation.

increase in internal energy = ……………………………… J [2]

18

© DHS 2014 9646/Prelim/03/14

For Examiner’s

Use

(c) The Singapore air pollution PSI index mostly depends on the concentration of PM2.5

particles in the air. PM2.5 particles are fine particles with diameters smaller than 2.5 µm.

Most of these fine particles are produced in peat fires and the dust produced were

found to contain heavy metals.

(i) Given that the density of heavy metal is 8000 kg m-3, calculate the maximum

possible mass of a PM2.5 particle.

mass = ……………………………… kg [2]

(ii) Estimate the root-mean-square speed of the PM2.5 particle in (c)(i) at 30°C.

root-mean-square speed = ……………………………… m s-1

[3]

(iii) Explain why haze from a new peat fire in Indonesia may reach Singapore within a

day, even though the peat fire is located more than 100 km away.

… … …………………………………………………………………………………………

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [2]

19

© DHS 2014


For Examiner’s

Use

(d) Fig. 7.2 shows how the concentration level of PM2.5 particles, n, is correlated to the

range of PSI index for moderate air quality.

n / µg m-3 PSI index

30 71

38 80

50 97

56 100

Fig. 7.2

(i) Thorium-232, a radioactive heavy metal, contributes up to 2% of the PM2.5

particles in mass. An air purifier removes 100% of the PM2.5 particles in a room

when the PSI index was 100 during the haze.

Determine the total number of thorium nuclei collected within the air purifier if the

volume of the room is 70 m3.

number = ……………………………… [3]

(ii) Thorium-232 has a very long half-life of 1.4 × 1010 years.

Calculate the activity due to the thorium nuclei collected in the air purifier.

activity = ……………………………… Bq [2]

(iii) Suggest why a Geiger-Muller tube is unable to detect the presence of Thorium-232

in the air purifier filter.

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [1]

20

© DHS 2014 9646/Prelim/03/14

For Examiner’s

Use

8 (a) Define electric potential at a point.

… … ……………………………………………………………………………………………

…………………… ………………………………………………………………………… [1]

(b) The magnitude of the potential gradient in an electric field is always equal to that of the

electric field strength.

Show that this is true for a uniform electric field E between two parallel plates at a

distance d apart when the potential difference between the plates is V.

[2]

(c) An isolated metal sphere A of radius r carries a charge of +Q. The charge may be

assumed to be concentrated at the centre of the sphere as shown in Fig. 8.1.

(i) On Fig. 8.1, draw the electric field lines around the isolated metal sphere. Use

arrows to show the direction of the field. [1]

(ii) Explain why the net electric charge of the conducting sphere resides entirely on its

surface.

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [2]

A

Fig. 8.1

21

© DHS 2014


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Use

(d) Sphere B is an uncharged metal sphere of radius 3r. It is placed at some fixed distance

away from metal sphere A. The separation between the spheres is much larger than the

radius of either sphere. The spheres are connected by a conducting wire as shown in

Fig. 8.2.

The system is allowed to reach electrostatic equilibrium with no further flow of charges.

(i) State the relationship between the potential of sphere A (VA) and sphere B (VB).

… ………………………………………………………………………………………… [1]

(ii) Find the ratio of the amount of charges at the surface of A to that of B.

ratio = ……………………………… [2]

(iii) Determine the ratio of the magnitudes of electric field strength at the surface of A to

that of B.

ratio = ……………………………… [2]

(e) A positively-charged metallic object of non-spherical shape is shown in Fig. 8.3.

Use your answers in (d) to draw the likely electric field lines around the object. [2]

B Fig. 8.2 (not to scale)

A

wire

3r r

Fig. 8.3

22

© DHS 2014 9646/Prelim/03/14

For Examiner’s

Use

(f) Two flat parallel metal plates are placed 2.3 cm apart, as shown in Fig. 8.4.

The potential difference between the plates is maintained at 210 V, resulting in a region

of uniform electric field between the plates.

A charged sphere +Q of mass 0.15 g travels with velocity v = 1.0 m s-1. It enters the

region uniform electric field through a small hole at position A at angle of θ = 25°. The

sphere exits the region through a small hole at position B. The distance between holes

A and B is 1.8 cm.

Ignoring the effects of gravity,

(i) determine the total time taken for the charged sphere to move from position A to B,

time = ……………………………… s [2]

(ii) calculate the magnitude of acceleration of the charged sphere after it has entered

the region between the parallel plates.

acceleration = ……………………………… m s-2 [2]

(iii) determine the amount of charge Q present on the sphere.

Q = ……………………………… C [2]

(iv) Explain how the horizontal distance travelled by the sphere would change if the

effects of gravity are not negligible.

… … …………………………………………………………………………………………

… ………………………………………………………………………………………… [1]

A

Fig. 8.4

2.3 cm

0 V

- 210 V

1.8 cm

B

θ

v

top plate

of 12

DHS Mark Scheme Syllabus

Year 6 Preliminary Examinations H2 Physics 2014 9646

Paper 1

Question Number

Key Question Number

Key

1 D 21 D

2 B 22 A

3 D 23 D

4 B 24 A

5 B 25 B

6 A 26 C

7 C 27 D

8 B 28 D

9 B 29 C

10 C 30 C

11 C 31 D

12 B 32 D

13 D 33 B

14 A 34 A

15 D 35 B

16 B 36 A

17 B 37 C

18 A 38 D

19 A 39 A

20 C 40 C

of 12

Paper 2

1 (a) KE =

( )( ) M1 [1]

(b) (i) ability to do work as a result of a change of shape of object B1 [1]

(b) (ii) loss in KE = gain in EPE

( )( ) C1

A1 [2]

(b) (iii) spring constant increases (by 2 times) C1

maximum compression reduces (is now 0.25 m) A1 [2]

(c) horizontal distance is the same for both tracks

average horizontal speed of trolley B is higher than that of A, M1

trolley B first as (horizontal) speed of B is faster down the valley A1 [2]

2 (a) waves must meet B1

waves must be of the same (transverse/longitudinal) type B1 [2]

waves must be of same polarization or both unpolarized (1 each, max 2)

(b) (i) to produce coherent sources at the two slits (S1 and S2) B1 [1]

(ii) intensity = k(amplitude)2 amplitude of each wave = √

resultant intensity = k(resultant amplitude) 2

[√

√

]

C1

= 4 A1 [2]

(iii) π rad OR 180° B1 [1]

(iv) light from s1 and s2 interferes destructively

leaves light from s3 at P M1

P not dark A1 [2]

3 (a) (i) arrow B is down the page B1 [1]

(ii) arrow F is towards Y B1 [1]

(iii) force is increasing as PQ approaches XY M1

PQ moves towards XY with increasing velocity and acceleration A1 [2]

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(b) (i) when CD is near PQ

the magnetic force on CD B1

(due to magnetic field generated by current in PQ)

is upwards and greater than weight of CD B1 [2]

(ii) as CD moves away from PQ, magnetic force decreases B1

CD can remain in equilibrium

when magnetic force on CD is equal to weight of CD B1 [2]

4 (a) (i) arrow from -0.85 eV level to -1.5 eV level B1 [1]

(ii)

C1

( )( ) C1

( )( )

( )( ) A1 [3]

(b) bright coloured background crossed by dark lines B1

two dark lines B1

electrons in gas atoms absorb photons with energies equal to

difference in orbital energy levels B1

light photons re-emitted randomly in all directions B1 [4]

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5 (a) resistance decreases with temperature B0

At higher temperatures, greater availability of thermal energy

Electrons from valence band can be promoted to conduction band,

leaving behind holes in the valence band. B1

negative-charged electrons in the conduction band and

positively-charged holes in the valence band

serve as mobile charge carriers B1

effect of having more free mobile charge carriers,

outweigh that of the increased lattice vibration

which disrupting smooth slow of the mobile charge carriers B1 [3]

(b) (i) 1 B1 [1]

(b) (ii) larger total resistance in circuit smaller current in DCHF M1

less resistive heating effect in thermistor, more accurate A1 [2]

OR

p.d. across HF decreases balance length decreases M1

percentage uncertainty in length increases, less accurate A1

(b) (iii)

( )( ) B1 [1]

(b) (iv) 1. 15.6 (read to nearest 0.1 ) B1 [1]

(b) (iv) 2.

B1 [1]

(b) (iv) 3. maximum power theorem: r = Rthermistor M1

A1 [2]

(b) (v) no thermal energy available

electrons cannot be promoted valence to conduction band

no conduction of electricity possible, infinite resistance M1

( ) A1 [2]

6 (a) More accurate at higher velocities A1

at low velocity, difference in pressure is small

percentage error in measurement is high. M1 [2]

(b) Take log on both sides of the equation

lg(q) = lg(ρ/2) + n lg(v) C1

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A graph of lg q against lg v will be a straight line A1

with gradient = n and y-intercept = lg (ρ/2) A1

if the equation is valid. [3]

(c) (i) 3.650 B1 [1]

(c) (ii) 1 plot to half square precision B1 [1]

(c) (ii) 2 Line of best fit plotted with balance points on both sides B1 [1]

(c) (iii) gradient =

M1

= 1.975 A1

3.855 = lg(ρ/2) + (1.975)(2.100) C1

ρ = 1.019 kg m-3

n = 1.975 A1 [4]

(d) (i) at lower altitude, PS is larger

blocked tube, no change in PT M1

q = PT – PS and hence the calculated v will decrease. A1 [2]

(ii) sensible answer eg ice,dirt B1 [1]

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7 Aim

Verify relationship between h and f

AND obtain k and n

Defining problem

{ in epen ent / r

epen ent / me re 1

keep magnitude of peak current / rms current in coil constant 1

Measurement

Labelled diagram: workable circuit with a.c. supply, coil, stand and ring 1

Signal generator / variable frequency power generator 1

Measure h with ruler/calipers 1

Measure f using oscilloscope/read off signal generator 1

Data Analysis

{

lg( ) = lg( ) lg( )

l t gr p lg( ) g in t lg( )

el ti n ip li i tr ig t line t ine 1

k = 10y-interecept and n = gradient (must show how to get k; part of aim) 1

Safety

Prevent coil overheating

e.g. switch off when not in use

Prevent injury from hot coil

e.g. do not touch hot coil, use gloves

(“ m ll c rrent ” n t ll we ) 1

Additional detail

Iron/steel retort stand clamped/secured to workbench

Measure h from opposite sides of ring/average/wait for stabilise

Method to keep magnitude of A.C. constant

Method of determining period from oscilloscope using time-base i.e. f = 1/T

Use coil of many turns/large current to have measurable heights

max 3 [12]

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Paper 3

1 (a) 0.4800 m (half smallest square 2 d.p.) B1 [1]

(b) k =

( )( )

( ) C1

= 18.7 N m-1 A1 [2]

(c)

8.38 rad s-1 B1 [1]

(d) (i) oscillations in the absence of an external force /

with no loss or gain in energy / constant amplitude B1 [1]

(ii)

M1

= 0.266 kg A1 [2]

(iii) either

( )( )

B1

or

read from m1 = 0.26 (nearest half square) x = 0.615 to 0.625 m B1 [1]

2 (a) displacement & direction of energy travel normal to one another B1 [1]

(b) (i) phase angle correct (need to see 1 ½ wavelengths) B1

leads T1 B1 [2]

(ii) waves must meet at the same place at the same time B1

resultant displacement = sum of individual displacements B1 [2]

(iii) 1. - ½A B1

2. -A B1

3. -3/2 A B1 [3]

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3 (a) induced e.m.f. in a conductor is directly proportional to

the rate of change of magnetic flux linkage B1 [1]

(b) (i) either

outer portions of metal cylinder cut more lines of magnetic flux

than inner portion per unit time B1

or

for the same angular velocity, outer portion cross-sectional area

of metal cylinder experiences larger rate than the inner portion

of change of magnetic flux linkage

therefore the outer portion is at a higher potential than inner portion B1 [2]

(ii) Lenz’ L w, irecti n in ce (e ) c rrent ct in irecti n

to produce effects to oppose the change causing it. B1

these currents dissipate heat energy M1

Less energy available for oscillations

amplitude decreases to zero eventually A1 [3]

4 (a) (i) Δy is the uncertainty in position. B1

It is linked to the slit width / w B1 [2]

(ii) Δp is the uncertainty in momentum B1

in the y-direction B1 [2]

(b) (i) uncertainty in y-momentum gives each electron some momentum

In the y-direction B1

It is random so the beam spreads out with some electrons

going to +y and others to –y B1 [2]

(ii) if w i m ller, t en Δy i m ller c t t Δp is larger B1

therefore more electrons scatter through larger angles B1 [2]

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5 (a) (i) A = 293

Z = 116 B1 [1]

(ii) total BE of reactants =

8.464048 × 48 + 7.307501 × 248 = 2218.534 MeV

total BE of products =

293 × 6.917282 = 2026.764 MeV C1

energy required = 191.77 MeV = 3.07 × 10-11 J A1 [2]

(iii) Either by conservation of momentum, products must have KE

Hence extra energy required

Or energy required to overcome repulsive forces

Or gamma photon(s) may be emitted in the process B1 [1]

(b) (i) decay not affected by external or environmental factors B1 [1]

(ii) correct shape

do not cut through y-axis or origin

gradient is steeper initially and gentle thereafter B1

correct position

Relative positions of Ca, Cm and Lv correct B1

Correct labels

Graph is labelled clearly and correctly

Not awarded if graph is not drawn or completely wrong B1 [3]

(iii) Fission product = 2 daughter nuclei of similar mass M1

From graph, BE per nucleon decreases (A 140)

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