Tang Shiu Kin Victoria Government Secondary School material1920/19-20 Mock Exam Paper… · Tang Shiu Kin Victoria Government Secondary School Mock Examination 2019 - 2020 Physics

P.1/19-20/ME/S.6/Physics 1A

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Tang Shiu Kin Victoria Government Secondary School

Mock Examination 2019 - 2020

Physics 1A

S.6 ( ) Date : 19-2-2020

Name: Time : 8:40 a.m. – 11:10 a.m.

Class No: Time Allowed : 2.5 hour

Total Marks : 129

Instructions:

1. There are TWO sections, A and B, in this Paper. Section A consists of multiple-choice

questions in this question book, while Section B contains conventional questions printed

separately in Question-Answer Book B. You are advised to finish Section A in about 50

minutes.

2. Answers to Section A should be marked on the Multiple-choice Answer Sheet while answers

to Section B should be written in the spaces provided in Question-Answer Book B. The

Answer Sheet for Section A and the Question-Answer Book for Section B must be

handed in separately at the end of the examination.

SECTION A (MULTIPLE-CHOICE QUESTIONS)

INSTRUCTIONS FOR SECTION A

1. Read the instructions on the Answer Sheet carefully.

2. When told to open this book, you should check that all the questions are there. Look for the

words ‘END OF SECTION A’ after the last question.

3. All questions carry equal marks. The total marks for this section is 45.

4. ANSWER ALL QUESTIONS. You are advised to use an HB pencil to mark all your

answers on the Answer Sheet, so that wrong marks can be completely erased with a rubber.

You must mark the answers clearly; otherwise you will lose marks if the answers cannot be

captured.

5. You should mark only ONE answer for each question. If you mark more than one answer,

you will receive NO MARKS for that question.

6. No marks will be deducted for wrong answers.



Section A Multiple Choices (33 questions, total 45 marks)

Questions marked with * involve knowledge of the extension component.

1. A student tries to calibrate a liquid-in-glass thermometer from the measurement of another

thermometer. The table below shows the length of the liquid column in the liquid-in-glass

thermometer at the calibration points.

Temperature / C Length / cm

25 7.8

100 15.9

Assume that the length of the liquid column increases linearly with the temperture. What is

the increase in length of the liquid column when the temperature increases by 10 C?

A 0.8 cm

B 1.1 cm

C 1.6 cm

D 3.1 cm

*2. An air column is trapped by a small liquid thread inside a capillary tube as shown. Initially,

the capillary tube is in a beaker of water at room temperature (state X). It is then immersed in

a hot water bath. The liquid thread moves up to a higher level and becomes steady (state Y).

Which of the following statements comparing states X and Y is INCORRECT?

A The number of molecules in the air column is the same in both states.

B The root-mean-square speed of the molecules in the air column is higher in state Y.

C The surface of the liquid thread is hit by the molecules in the air column more often in

state Y.

D The weight of the liquid column is the same in both states.

state X state Y

capillary tube

air column

liquid thread

water at room

temperature

hot water

bath



3. When 15 g of water at 25 C is poured onto a hot frying pan, all the water becomes steam at

100 C. Find the decrease in temperature of the frying pan.

Given: heat capacity of frying pan = 350 J C–1

specific heat capacity of water = 4200 J kg–1

C–1

specific latent heat of vaporization of water = 2.26 106 J kg

–1

A 6.25 C

B 13.5 C

C 96.9 C

D 110 C

4. On a hot summer day, the wind blows from the sea to the land. Which of the following is a

possible reason?

A The sea is hotter than the land.

B The land is hotter than the sea.

C The sea is a better conductor of heat than the land.

D The land is a better conductor of heat than the sea.

5. Tony lies without moving on a surface with inclination to the horizontal. The magnitude of

the normal force and the friction acting on him is N and f respectively. Which of the following

graphs is/are correct?

(1)

(2)

(3)

A (2) only B (3) only

C (1) and (2) only D (2) and (3) only

f

sin 0

N + f

0

N

cos 0



6. Cities X and Y are connected by a straight road. Car M travels from X to Y while car N travels

from Y to X. Both cars start at t = 0 and reach their destinations at t = 100 min. Their vt

graphs are shown below. (The directions towards their own destinations are taken as positive.)

Which of the following correctly describes the time and position where the two cars meet each

other?

Meeting time Meeting position

A

at t = 50 min midway between cities X and Y

B

at t = 50 min closer to city Y

C

t 50 min midway between cities X and Y

D

t 50 min closer to city Y

7. A tennis ball is thrown upwards. It takes time t to reach the maximum height. How long it

takes to halve its kinetic energy from the moment it is thrown upwards?

A 0.29t

B 0.35t

C 0.5t

D 0.65t

*8. A volleyball flies to the opponent side after serving. If air resistance is not negligible, when

the volleyball reaches the highest point, which of the following statements is correct?

A The vertical component of the volleyball’s acceleration is zero.

B The horizontal component of the volleyball’s acceleration is zero.

C The vertical component of the volleyball’s momentum is zero.

D The horizontal component of the volleyball’s momentum is zero.

v

t / min 0 100 50

car M

car N



9. A wooden block of mass 100 kg lies on a light plank at a point 1 m from one end as shown.

The length of the plank is 4 m. To lift the block, what is the minimum force F needed to exert

on the other end of the plank?

A 24.5 N

B 40.8 N

C 245 N

D 408 N

10. A stationary pin of 1.5 kg is hit head-on by a bowling ball of 4 kg. The speed of the bowling

ball just before collision is 5 m s–1

.

Assuming that the collision is elastic, estimate the final speed of the bowling ball.

A 0 B 2.27 m s–1

C 4.55 m s–1

D 7.27 m s–1

*11. Three balls A, B and C start motion from the same height above the ground as shown in the

following figure. A and B have an initial horizontal velocity while C starts motion from rest.

They respectively take times tA, tB and tC to reach the ground.

A B C

Which of the following is correct?

A tA = tB = tC

B tA > tB = tC

C tA = tB > tC

D tA > tB > tC



*12. On the surface of a planet with mass M and radius R, the gravitational acceleration is g. The

gravitational acceleration on the surface of a planet with mass 2M and radius 2R is

A 2g

B g2

C g

D 2

g

*13. Two balls M and N are moving in uniform circular motion at different heights on a

funnel-shaped device as shown. The masses of the balls are the same.

Which of the following statements comparing M and N is INCORRECT?

A M has a higher angular speed.

B M has a higher kinetic energy.

C M has a higher potential energy.

D M takes a longer time to complete one revolution.

14. One end of a string is connected to a vibrator and the other end is fixed on a wall. The length

of the string is 1.2 m. At time t = 0, the vibrator starts to vibrate at 10 Hz and produces a

travelling wave of amplitude 5 cm towards the wall. The wave travels along the string at

4 ms1

. Which of the following statements about the stationary wave formed is correct?

A A stationary wave is observed on the whole string starting from t = 0.3 s.

B The amplitude of the stationary wave at an antinode is 5 cm.

C No stationary wave can be formed.

D The stationary wave appears as one with 6 loops due to the persistence of vision of the

eyes.

M

N



15. Two coherent sources produce circular waves in a ripple tank. The figure below shows the

wavefronts at a certain instant. Solid lines represent crests and dotted lines represent troughs.

P, Q and R are water molecules as indicated in the diagram. Which of them is/are at rest at

that instant?

A P only

B Q only

C P and R only

D P, Q and R

16. The displacementtime graph of a particle on a longitudinal wave is shown below. The

rightward displacement is taken as positive.

In which direction was the particle moving at t = t1?

A Upwards

B Downwards

C Rightwards

D Leftwards

R Q

P

S2 S1



17. A car travels at constant speed 30 m s1

towards a cliff. At time t = 0, the car is at 340 m from

the cliff and it makes a honk. At what time would the driver hear the echo of the honk?

Given: speed of sound = 340 m s1

A At t = 2 s B At t = 2.19 s

C At t = 1.83 s D At t = 1.13 s

*18. A monochromatic light ray is directed onto a plane transmission grating and the 2nd-order

bright fringe is produced at 43. Totally how many bright fringes can be observed?

A 2 B 3

C 4 D 5

*19. A lens is placed in front of an object. The focal length of the lens is 12 cm. A virtual image is

formed at a distance of 10 cm from the lens. Which of the following lenses is used and what is

the object distance?

Type of lens Object distance

A concave 5.5 cm

B concave 60 cm

C convex 5.5 cm

D convex 60 cm

20.

55 air

medium X

A ray of monochromatic light enters a solid transparent medium X from air. The incident ray

makes an angle of 55 with the boundary plane as shown. Which of the following statements

is/are correct?

(1) The higher the speed of light in medium X, the smaller the angle of refraction.

(2) The angle of refraction must be smaller than 35.

(3) Dispersion of light will occur in medium X.

A (1) only B (2) only

C (1) and (2) only D (1) and (3) only



(For Q2122.) A longitudinal wave travels past a series of particles on a spring from left to right

with a speed of 40 cm s1

. The figure below shows the equilibrium positions of the particles and

their positions at time instant t.

21. Which of the following particles is momentarily at rest at time instant t?

A Particle E B Particle F

C Particle G D Particle H

22. What is the period of the longitudinal wave?

A 0.5 s

B 1.0 s

C 2.0 s

D Cannot be determined

23. Two oppositely charged parallel metal plates are separated by a small distance d. The electric

field strength between the plates is E. An electron of mass m and charge –e enters the space

between the two plates as shown.

Which of the following correctly gives the magnitude and direction of the acceleration of the

electron as it travels between the plates?

Magnitude Direction

A m

eE same as the electric field

B m

eE opposite to the electric field

C md

eE same as the electric field

D md

eE opposite to the electric field

time t

equilibrium

positions

+ + + + + +

+ + + +

– – – – – –

– – – –

e–

d



24. M and N are two resistive wires of the same length and thickness. A student passes currents I

of different sizes from 2 A to 10 A through each wire and measures the corresponding

voltages V across the wire. The result is shown in the graph below.

V

I / A

M

N

0 2 6 8 10

Which of the following statements are correct?

(1) Wire M obeys Ohm’s law from I = 2 A to I = 8 A.

(2) The two wires have the same resistance when I = 6 A.

(3) The resistance of M is greater than that of N from I = 2 A to I = 6 A.

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)

25.

In the network of resistors shown, the resistance across terminals X and Y is 99 . When

switch S is opened, what is the resistance across terminals X and Y?

A Between 99 and 100

B Between 49 and 99

C Smaller than 49

D Larger than 100

X Y 100

R R

S



26. An electric toaster is rated at ‘220 V, 1100 W’. Which of the following fuses should be

assembled to the power switch of the toaster?

A 3 A B 5 A

C 8 A D 13 A

27. A circuit is connected as shown in the figure below. The internal resistance of the power

supply is zero.

d.c. power supply

V

A

By assuming both the ammeter and the voltmeter are ideal, i.e. the resistance of the ammeter

is zero and the resistance of the voltmeter is inifnite, the readings of the ammeter and the

voltmeter are predicted to be I and V respectively. Which of the following statements is

correct?

A If only the voltmeter is ideal, the reading of the ammeter is smaller than I.

B If only the ammeter is ideal, the reading of the ammeter is smaller than I.

C If only the ammeter is ideal, the reading of the voltmeter is smaller than V.

D If only the voltmeter is ideal, the reading of the ammeter is larger than I.

*28. A transformer is connected in a circuit as shown.

The primary coil is connected to a 250 V a.c. supply while the secondary coil is connected with

a light bulb rated ’10 V, 5 W’. Given that the current in primary coil is 0.025 A and the light

bulb operates at its rated value. Assume the primary and secondary coils have negligible

resistance. Find the efficiency of the transformer.

A 80% B 72%

C 64% D 91%



*29. A straight conductor PQ is moving downwards at a steady speed of 0.5 m s1

between two

magnets. The conductor has a resistance of 0.5 and is connected to a 3 mV battery. The

magnets have pole faces of 0.2 m0.1 m and the magnetic flux density between them is 3 mT.

conductor

N

S

0

+ _

P

Q

0.1 m

0.2 m

3 mV

What is the reading of the galvanometer when the conductor is moving between the magnets?

A 5.4 103

A

B 5.7 103

A

C 6.0 103

A

D 6.3 103

A

30. Three different particles X,Y and Z enter a region of uniform magnetic field into the paper as

shown.

All the particles have the same incident speed but their masses and charges are unknown.

Which of the following statements are correct?

(1) Particles X and Y carry unlike charges.

(2) If particles X and Y carry the same amount of charge, X is more massive than Y.

(3) Particle Z is uncharged.

A (1) and (2) only

B (1) and (3) only

C (2) and (3) only

D (1), (2) and (3)



31. α radiation deflects in a magnetic field but γ radiation does not. Which of the following

statements best explains this phenomenon?

A α radiation has mass but γ radiation has no mass.

B α radiation is charged but γ radiation is uncharged.

C α radiation has a speed lower than γ radiation.

D α radiation has a range much shorter than γ radiation in air.

32. The following shows some nuclear reactions.

What do X and Y represent?

X Y

A An α particle An α particle

B An α particle Four neutrons

C A β particle An α particle

D A β particle Four neutrons

*33 A possible nuclear reaction is shown below.

Which of the following quantities is/are conserved during the process?

(1) Total number of nucleon

(2) Total mass

(3) Total mass–energy

A (1) only

B (3) only

C (1) and (3) only

D (2) and (3) only

End of Section A



List of data, formulae and relationships

Data

molar gas constant R = 8.31 J mol1

K1

Avogadro constant NA = 6.02 1023

mol1

acceleration due to gravity g = 9.81 m s2

(close to the Earth)

universal gravitational constant G = 6.67 1011

N m2 kg

2

speed of light in vacuum c = 3.00 108 m s

1

charge of electron e = 1.60 1019

C

electron rest mass me = 9.11 1031

kg

permittivity of free space 0 = 8.85 1012

C2 N

1 m

2

permeability of free space 0 = 4 107

H m1

atomic mass unit u = 1.661 1027

kg (1 u is equivalent to 931 MeV)

astronomical unit AU = 1.50 1011

m

light year ly = 9.46 1015

m

parsec pc = 3.09 1016

m = 3.26 ly = 206 265 AU

Stefan constant = 5.67 108

W m2

K4

Planck constant h = 6.63 1034

J s

Rectilinear motion Mathematics

For uniformly accelerated motion:

v =u + at

s=ut + 2

2

1at

v2=u

2 + 2as

Equation of a straight line y = mx + c

Arc length = r

Surface area of cylinder = 2rh + 2r2

Volume of cylinder = r2h

Surface area of sphere = 4r2

Volume of sphere = 3π3

4r

For small angles, sin tan (in radians)

Astronomy and Space Science

U =r

GMm gravitational potential energy

P = AT4 Stefan’s law

0f

f

c

v

0λ

λ Doppler effect

Energy and Use of Energy

AE

illuminance

t

Q=

d

TTA )( CH rate of energy transfer by conduction

U =d

thermal transmittance U-value

P = 3

2

1Av maximum power by wind turbine

Atomic World

2

maxe2

1vm = hf Einstein’s photoelectric equation

En =

2

0

2

4

e

28

1

h

em

n=

2

6.13

n eV

energy level equation for hydrogen atom

=p

h=

mv

h de Broglie formula

d

λ22.1 Rayleigh criterion (resolving power)

Medical Physics

d

λ22.1 Rayleigh criterion (resolving power)

power =f

1 power of a lens

L =0

log10I

I intensity level (dB)

Z = c acoustic impedance

=0

r

I

I=

2

12

2

12

)(

)(

ZZ

ZZ

intensity reflection coefficient

xeII 0 transmitted intensity through a

medium



A1. E = mcT

energy transfer

during heating and

cooling

D1. F =2

0

21

π4 r

QQ

Coulomb’s law

A2. E = lm

energy transfer

during change of

state

D2. E =2

0π4 r

Q

electric field strength due to a

point charge

A3. pV = nRT equation of state for

an ideal gas D3. E =

d

V

electric field between parallel

plates (numerically)

A4. pV = 2

3

1cNm

kinetic theory

equation D4. R =

A

l resistance and resistivity

A5. EK =A2

3

N

RT

molecular kinetic

energy D5. R = R1 + R2 resistors in series

D6. R

1=

1

1

R+

2

1

R resistors in parallel

B1. F =t

vm

=

t

p

force D7. P = IV = I

2R power in a circuit

B2. moment = F d moment of a force D8. F = BQv sin force on a moving charge in a

magnetic field

B3. EP = mgh gravitational

potential energy D9. F = BIl sin

force on a current-carrying

conductor in a magnetic field

B4. EK = 2

2

1mv kinetic energy D10. B =

r

I

π2

0 magnetic field due to a long

straight wire

B5. P = Fv mechanical power D11. B =l

NI0 magnetic field inside a long

solenoid

B6. a =r

v 2

= 2r

centripetal

acceleration D12. =

tN

induced e.m.f.

B7. F =2

21

r

mGm

Newton’s law of

gravitation D13.

p

s

V

V

p

s

N

N

ratio of secondary voltage to

primary voltage in a

transformer

C1. y =a

λD

fringe width in

double-slit

interference

E1. N = N0ekt

law of radioactive decay

C2. d sin = n diffraction grating

equation E2.

2

1t =k

2ln half-life and decay constant

C3. vu

11 =

f

1

equation for a

single lens E3. A = kN

activity and the number of

undecayed nuclei

E4. E = mc2 mass-energy relationship

P.1/19-20/ME/S.6/Physics 1B Go on to the next page

nnex

Tang Shiu Kin Victoria Government Secondary School

Mock Examination 2019 - 2020

Physics 1B

S.6 ( ) Date :19-2-2020

Name: Time : 8:40 a.m. – 11:10 a.m.

Class No: Time Allowed : 2.5 hours

Total Marks : 129

Instructions:

Section B : Question – Answer Book B

1. This section carries 84 marks. Answer ALL questions.

2. Write your answers in the spaces provided in this Question – Answer Book.

3. The diagrams in this section are NOT necessarily drawn to scale.

Question No. Marks Question No. Marks

1 /8 6 /6

2 /8 7 /7

3 /10 8 /10

4 /10 9 /8

5 /8 10 /9

Total /84


nnex

Section B: Answer ALL questions. Parts marked with * involve knowledge of the extension

component. Write your answers in the spaces provided.

1 Figure 1.1 shows the set-up of an experiment for finding the specific heat capacity c of a liquid.

A glass tube containing a heating coil is fitted into a vacuum container. The liquid is pumped

into the glass tube and heated by the coil. The mass of liquid passing through the tube in one

second is m. The voltage V across the coil and the current I passing through the coil are adjusted

so that the temperature difference T2 – T1 is small but measureable.

The following table shows the result obtained from the experiment.

I 2.0 A

V 50 V

m 0.01 kg

T1 25 °C

T2 30 °C

(a) What is the use of the vacuum container? (1 mark)

(b) Find the energy supplied to the liquid by the heating coil in one second. (2 marks)

(c) Assume the energy lost to the surroundings is negligible. Using the result in (b), find the

specific heat capacity of the liquid. (3 marks)

Figure 1.1

heating coil in

glass tube

vacuum container

liquid in liquid out

power supply R

T1

T2


nnex

1. (d) Suggest a way by which energy is lost from the set-up to the surroundings. (1 mark)

(e) The flow rate of liquid is slightly reduced. How should the variable resistor R be adjusted so

that the temperature difference T2 – T1 remains unchanged? (1 mark)

*2 Amy has a bowl with a lid as shown in Figure 2.1. The lid is a rigid and unbendable disk which can seal

the bowl tightly. The weight of the lid is 0.3 N.

Figure 2.1

The air temperature and pressure in the room is 15 C and 100 kPa respectively. Amy pours some warm

soup into the bowl and then covers the bowl with the lid. The mouth of the bowl has a cross-sectional

area of 100 cm2. A layer of oil floating on the soup prevents evaporation and keeps the air inside the

bowl dry.

(a) The temperature of the soup and air inside the bowl is 30 °C when the lid is closed. After a certain

time, the temperature inside the bowl drops to the room temperature.

(i) Estimate the new air pressure inside the bowl. (2 marks)

(ii) Explain how the air pressure change using the kinetic theory of gases. (2 marks)

(b) Amy pulls the handle of the lid and finds it difficult to open. Estimate the minimum force required

to lift the lid. (2 marks)

(c) Estimate the change of average kinetic energy of air particle in the bowl. (2 marks)

lid

soup

a layer of oil


nnex

3. A car moved with constant speed along a straight road. Suddenly the driver saw a bus stopped in

front of his car at t = 0. He then applied the brake, but the car still hit the bus at t = 4 seconds. The

variation of the speed v of the car with time t is shown in Figure 3.1. The total mass of the car and

the driver is 2400 kg.

Figure 3.1

(a) Find the reaction time of the driver from the graph. (1 mark)

(b) What was the separation between the car and the bus at the moment the driver saw the bus.

(2 marks)

(c) Find the deceleration of the car and the decelerating force acting on the car by the brake

before the collision. (3 marks)

(d) What was the impact force acting on the car during the collision? (2 marks)

(e) The bus had a mass of 15000 kg. After the collision, the bus moved forward with a speed

1.6 ms−1

. Was the collision elastic or inelastic? (2 marks)


nnex

4. Aeroplane Olives (飛機欖) were popular in Hong Kong decades ago. People shouted from their

flats to the street vendor if they wanted to buy some olives. They would throw money to the

vendor and the vendor would throw the olives into their flats.

Figure 4.1

Suppose a vendor wanted to throw some olives to a flat in the third floor (Figure 4.1).

At time t = 0, he threw a packet of olives from point O which is 1 m above the ground with an

initial velocity of 16 m s1

and an angle of projection of 80. The packet passed the highest point

A before entering the flat at B which was 12 m above the ground. Neglect air resistance.

*(a) Find the height of A. (2 marks)

(b) By considering the energy of the olive packet, find its speed at B. (3 marks)

*(c) In Figure 4.2, sketch the graph showing the variation of the kinetic energy (KE) of the olive

packet against time t before reaching B. (2 marks)

A B

O

12 m

1 m

80

16 m s1

Figure 4.2


nnex

4. *(d) Calculate the horizontal distance between point O and the wall of building. (3 marks)

5. Figure 5.1 shows an object AB placed in front of a lens L. The line XY is the principal axis of L.

A light ray from A is refracted by L.

X Y

L

A

5 cm

B

Figure 5.1

(a) (i) What kind of lens is L? Explain briefly. (2 marks)

(ii) By drawing a suitable line(s) in Figure 5.1, find the focal length of L and draw the

image formed by the lens L. (3 marks)

focal length of L =

(b) Now object AB is removed and three parallel light rays are incident on L, as shown in

Figure 5.2. Draw the refracted rays. (3 marks)

X Y

L 5 cm

Figure 5.2


nnex

6. You are given a ripple tank, a bar-shaped vibrator with adjustable frequency and two long

straight barriers. With the aid of a diagram, describe an experiment to investigate TWO factors

affecting the degree of diffraction when plane waves pass through a small gap. (6 marks)


nnex

7. A light ray of wavelength is directed to a plane transmission grating which has 5000 lines per

cm(5000 cm-1

). The maximum order of bright fringe that can be projected on a screen is 3.

(a) If the value of is about 6 107

m, estimate the frequency of the light ray. (2 marks)

(b) Explain briefly, according to the theory of interference, how the bright fringes on the screen

are formed. (2 marks)

*(c) Find the maximum and minimum possible values of . (3 marks)


nnex

8. In Figure 8.1, two identical bulbs X and Y of rating ‘3 V, 0.15 W’ are connected in parallel to a

3 V battery. Switch S can turn on or off the lamps. When switch S is open, the measured voltage

across the battery is 3.00 V. When switch S is closed, the measured voltage across the battery

drops to 2.95 V.

Y

X

S

3 V

V

Figure 8.1

(a) Explain why the voltage across the battery drops when switch S is closed. (1 mark)

(b) (i) Find the equivalent resistance of the two bulbs. (2 marks)

(ii) Find the total power output of the two bulbs when switch S is closed. (2 marks)

*(c) In Figure 8.2, the two bulbs are now connected in parallel to the 220 V a.c. mains via a

C-core transformer with 150 turns in its secondary coil. The efficiency of the transformer is

90.0%.

Y

X

220 V a.c. ~ S

Ns = 150

Figure 8.2

(i) Find the number of turns in the primary coil such that the two bulbs X and Y work at

their rated voltage. (2 marks)


nnex

8. (c) (ii) Find the peak value of the alternating current in the primary coil. (2 marks)

(d) Suggest ONE way to increase the efficiency of the transformer. (1 mark)

9.

× × × × × × ×

× × × × × × ×

× × × × × × ×

× × × × × × ×

Q P

R S

v

0.1 m

Figure 9.1

In Figure 9.1, an external force (not shown) is applied to move a conducting square coil of length

0.1 m into a uniform magnetic field of 0.6 T pointing into the paper. The coil is moving with a

constant velocity v = 0.02 m s–1

towards the right.

Given the total resistance of the coil is 2 .

(a) *(i) Find the induced e.m.f. ε in the coil. (2 marks)

(ii) Draw the direction of the induced current in the coil in Figure 9.1 as it moves into the

magnetic field. (1 mark)

*(iii) By (i), find the size of the induced current I in the coil. (1 mark)

(b) Find the work done on the coil by the external force in the process. Hence or otherwise,

find the external force needed to in the above process. (4 marks)


nnex

10. Read the following article about a nuclear accident and answer the questions that follow.

In March 2011, a serious nuclear accident happened at the Fukushima Daiichi Nuclear

Power Plant in Japan. A considerable amount of radioactive substances including

iodine-131 (I-131) was released into air and oceans. I-131 at above safe levels was

detected in local water supply and various kinds of food. Fortunately, I-131 has a short

half-life of 8 days.

Our body tissues, especially the thyroid, absorb iodine present in water and food. I-131

emits β radiation and a high intake of it may hazardous to health.

In case of an emergency, the non-radioactive isotope of iodine (I-127), usually in the

form of a potassium iodide tablet, can be taken to block the absorption of I-131.

(a) What are isotopes? (1 mark)

(b) The following equation shows how I-131 is produced in a nuclear reaction:

nU 10

23592 n3YI 1

03913153 x

(i) Find the value of x. (1 mark)

(ii) Identify the type of nuclear reaction that the equation represents. Explain your answer

briefly. (2 marks)

(c) Explain why a high intake of I-131 is hazardous to health. (2 marks)

(d) A fish sample contaminated by I-131 has an activity of 4000 Bq per kilogram. The safety

limit for I-131 in fish is 100 Bq per kilogram. At least how many days are required for the

I-131 content in the contaminated fish to drop to the safety limit? Show your calculation.

(3 marks)

End of Paper

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