Physics 2022 May/June | Past Paper

Q1(a)

Short Answer 1 mark

(i) Define gravitational potential at a point.

Q1(ii)

Short Answer 1 mark

Starting from the equation for the gravitational potential due to a point mass, show that the gravitational potential energy E of a point mass m at a distance r from another point mass M is given by= -GMm where G is the gravitational constant.

Q1(b)

Short Answer 1 mark

Fig. 1.1 shows the path of a comet of mass 2.20 × 10 kg as it passes around a star of mass 1.99 × 10kg. 34.1 km s comet mass 2.20 × 10 star mass 1.99 × 10 path of comet Fig. 1.1 (not to scale) At point X, the comet is 8.44 × 10 m from the centre of the star and is moving at a speed of 34.1 km s At point Y, the comet passes its point of closest approach to the star. At this point, the comet is a distance of 6.38 × 10 m from the centre of the star. Both the comet and the star can be considered as point masses at their centres.

Q1(i)

Short Answer 2 marks

Calculate the magnitude of the change in the gravitational potential energy ΔE of the comet as it moves from position X to position Y. = J

Q1(ii)

Short Answer 1 mark

State, with a reason, whether the change in gravitational potential energy in (b)(i) is an increase or a decrease.

Q1(iii)

Short Answer 3 marks

Use your answer in (b)(i) to determine the speed, in km s , of the comet at point Y. speed = km s

Q1(c)

Short Answer 1 mark

A second comet passes point X with the same speed as the comet in

Q1(c)(b)

Short Answer 1 mark

and travelling in the same direction. This comet is gradually losing mass. The mass of this comet when it passes point X is the same as the mass of the comet in

Q1(c)(b)

Short Answer 1 mark

. Suggest, with a reason, how the path of the second comet compares with the path shown in Fig. 1.1. [Total: 10]

Q2(a)

Short Answer 1 mark

State Coulomb's law.

Q2(b)

Short Answer 1 mark

Positronium is a system in which an electron and a positron orbit, with the same period, around their common centre of mass, as shown in Fig. 2.1. centre of mass electron positron Fig. 2.1 (not to scale) The radius r of the orbit of both particles is 1.59 × 10-10

Q2(i)

Short Answer 1 mark

Explain how the electric force between the electron and the positron causes the path of the moving particles to be circular.

Q2(ii)

Short Answer 2 marks

Show that the magnitude of the electric force between the electron and the positron is 2.28 × 10

Q2(iii)

Short Answer 3 marks

Use the information in (b)(ii) to determine the period of the circular orbit of the two particles. period = s

Q2(c)

Short Answer 1 mark

Positronium is highly unstable, and after a very short period of time it becomes gamma radiation.

Q2(i)

Short Answer 1 mark

Describe how gamma radiation is formed from the two particles in positronium.

Q2(ii)

Short Answer 1 mark

State one medical application of the process described in (c)(i). [Total: 13]

Q3(a)

Short Answer 1 mark

Define specific latent heat of vaporisation.

Q3(b)

Short Answer 1 mark

The specific latent heat of vaporisation of water at atmospheric pressure of 1.0 × 10 Pa is 2.3 × 10 J kg . A mass of 0.37 kg of liquid water at 100 °C is provided with the thermal energy needed to vaporise all of the water at atmospheric pressure.

Q3(i)

Short Answer 1 mark

Calculate the thermal energy q supplied to the water. q = J

Q3(ii)

Short Answer 3 marks

The mass of 1.0 mol of water is 18 g. Assume that water vapour can be considered to behave as an ideal gas. Show that the volume of water vapour produced is 0.64 m

Q3(iii)

Short Answer 2 marks

Assume that the initial volume of the liquid water is negligible compared with the volume of water vapour produced. Determine the magnitude of the work done by the water in expanding against the atmosphere when it vaporises. work done = J

Q3(iv)

Short Answer 1 mark

Use your answers in

Q3(iv)(iii)

Short Answer 1 mark

to determine the increase in internal energy of the water when it vaporises at 100 °C. Explain your reasoning. increase in internal energy = J

Q3(c)

Short Answer 1 mark

Use the first law of thermodynamics to suggest, with a reason, how the specific latent heat of vaporisation of water at a pressure greater than atmospheric pressure compares with its value at atmospheric pressure. [Total: 12]

Q4(a)

Short Answer 1 mark

State what is meant by resonance.

Q4(b)

Short Answer 1 mark

Fig. 4.1 shows a heavy pendulum and a light pendulum, both suspended from the same piece of string. This string is secured at each end to fixed points. fixed points string heavy pendulum light pendulum Both pendulums have the same natural frequency. The heavy pendulum is set oscillating perpendicular to the plane of the diagram. As it oscillates, it causes the light pendulum to oscillate. Fig. 4.2 shows the variation with time t of the displacements of the two pendulums for three oscillations. t / s 0 displacement / cm heavy light The variation with t of the displacement x of the light pendulum is given by x = 0.25 sin 5.0rt where x is in centimetres and t is in seconds.

Q4(i)

Short Answer 2 marks

Calculate the period T of the oscillations. T = s

Q4(ii)

Short Answer 2 marks

On Fig. 4.2, label both of the axes with the correct scales. Use the space below for any additional working that you need.

Q4(iii)

Short Answer 1 mark

Determine the magnitude of the phase difference φ between the oscillations of the light and heavy pendulums. Give a unit with your answer. φ = unit [2] [Total: 8]

Q5(a)

Short Answer 1 mark

Define the capacitance of a parallel plate capacitor.

Q5(b)

Short Answer 3 marks

Two capacitors, of capacitances C and C , are connected in parallel to a power supply of electromotive force (e.m.f.) E, as shown in Fig. 5.1. Show that the combined capacitance C of the two capacitors is given by= C+ C Explain your reasoning. You may draw on Fig. 5.1 if you wish.

Q5(c)

Short Answer 1 mark

Two capacitors of capacitances 22 μF and 47 μF, and a resistor of resistance 2.7 MΩ, are connected into the circuit of Fig. 5.2. 12 V 2.7 MΩ 22 μF 47 μF The battery has an e.m.f. of 12 V.

Q5(i)

Short Answer 1 mark

Show that the combined capacitance of the two capacitors is 15 μF.

Q5(ii)

Short Answer 2 marks

The two-way switch S is initially at position X, so that the capacitors are fully charged. Use the information in (c)(i) to calculate the total energy stored in the two capacitors. total energy = J

Q5(iii)

Short Answer 1 mark

The two-way switch is now moved to position Y. Determine the time taken for the potential difference (p.d.) across the 22 μF capacitor to become 6.0 V. time = s [3] [Total: 11]

Q6(a)

Short Answer 2 marks

State the two conditions that must be satisfied for a copper wire, placed in a magnetic field, to experience a magnetic force. 1 2

Q6(b)

Short Answer 1 mark

A long air-cored solenoid is connected to a power supply, so that the solenoid creates a magnetic field. Fig. 6.1 shows a cross-section through the middle of the solenoid. section through solenoid wires The direction of the magnetic field at point W is indicated by the arrow. Three other points are labelled X, Y and Z.

Q6(i)

Short Answer 3 marks

On Fig. 6.1, draw arrows to indicate the direction of the magnetic field at each of the points X, Y and Z.

Q6(ii)

Short Answer 2 marks

Compare the magnitude of the flux density of the magnetic field:

Q6(c)

Short Answer 1 mark

Two long parallel current-carrying wires are placed near to each other in a vacuum. Explain why these wires exert a magnetic force on each other. You may draw a labelled diagram if you wish. [Total: 10]

Q7(a)

Short Answer 1 mark

State Faraday's law of electromagnetic induction.

Q7(b)

Structured 4 marks

Two coils are wound on an iron bar, as shown in Fig. 7.1. iron bar coil 2 coil 1 Coil 1 is connected to a potential difference (p.d.) V that gives rise to a magnetic field in the iron bar. Fig. 7.2 shows the variation with time t of the magnetic flux density B in the iron bar. 0.1 0.2 0.3 0.40 t / s A voltmeter measures the electromotive force (e.m.f.) V that is induced across coil 2. On Fig. 7.3, sketch the variation with t of V between t = 0 and t = 0.40 s. 0.1 0.2 0.3 0.40 t / s

Q7(c)

Short Answer 1 mark

Coil 2 in

Q7(c)(b)

Short Answer 1 mark

is now replaced with a copper ring that rests loosely on top of coil 1. The supply to coil 1 is replaced with a cell and a switch that is initially open, as shown in Fig. 7.4. iron bar copper ring coil 1

Q7(i)

Short Answer 1 mark

The switch is now closed. As it is closed, the copper ring is observed to jump upwards. Explain why this happens.

Q7(ii)

Short Answer 1 mark

Suggest, with a reason, what would be the effect of repeating the procedure in (c)(i) with the terminals of the cell reversed. [Total: 10]

Q8(a)

Short Answer 1 mark

State one piece of experimental evidence for:

Q8(i)

Short Answer 1 mark

the particulate nature of electromagnetic radiation

Q8(ii)

Short Answer 1 mark

the wave nature of matter.

Q8(b)

Short Answer 3 marks

(i) Calculate the de Broglie wavelength λ of an alpha-particle moving at a speed of 6.2 × 10m s λ = m

Q8(ii)

Short Answer 2 marks

The speed v of the alpha-particle in (b)(i) is gradually reduced to zero. On Fig. 8.1, sketch the variation with v of λ. 0 6.2 v / 10m s

Q8(c)

Short Answer 1 mark

Suggest an explanation for why people are not observed to diffract when they walk through a doorway. [Total: 8]

Q9(a)

Short Answer 1 mark

(i) State Hubble's law.

Q9(ii)

Short Answer 1 mark

Explain how cosmologists use observations of emission spectra from stars in distant galaxies to determine that the Universe is expanding.

Q9(b)

Short Answer 1 mark

Explain how Hubble's law and the idea of the expanding Universe lead to the Big Bang theory of the origin of the Universe. [Total: 7]

Q10(a)

Short Answer 1 mark

State what is meant by radioactive decay.

Q10(b)

Short Answer 1 mark

A radioactive sample consists of an isotope X of half-life T that decays to form a stable product. Only X and the stable product are present in the sample. At time t = 0, the sample has an activity of A and contains N nuclei of X.

Q10(i)

Short Answer 3 marks

On Fig. 10.1, sketch the variation with t of the number N of nuclei of X present in the sample. Your line should extend from time t = 0 to time t = 3T. 0 T 2T 3T 0.25N 0.50N 0.75N 1.00N

Q10(ii)

Short Answer 2 marks

On Fig. 10.2, sketch the variation with N of the activity A of the sample for values of N between N = 0 and N = N 0.5A 0.5N 1.0N 1.0A

Q10(c)

Short Answer 1 mark

State the name of the quantity represented by the gradient of your line in:

Q10(i)

Short Answer 1 mark

Fig. 10.1

Q10(ii)

Short Answer 1 mark

Fig. 10.2.

Q10(d)

Short Answer 1 mark

For the sample in

Q10(d)(b)

Short Answer 1 mark

, calculate the fraction at time t = 1.70T. = [2] [Total: 11] Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cambridgeinternational.org after the live examination series. Local Examinations Syndicate (UCLES), which is a department of the University of Cambridge.

Board	CAIE
Level	A Level
Subject	Physics
Code	`9702`
Year	2022
Session	May/June
Q&A	65 questions

Physics 2022 · May/June

Questions & Model Answers 65 Qs

Paper Details