Physics 2023 Oct/Nov | Past Paper

Q1(a)

Short Answer 1 mark

Define the radian.

Q1(b)

Short Answer 2 marks

The minute hand of a clock revolves at constant angular speed around the face of the clock, completing one revolution every hour. A small piece of modelling clay is attached to the hand with its centre of gravity at a distance L from the fixed end of the hand, as shown in Fig. 1.1. free end face of clock modelling clay direction of revolution of minute hand minute hand fixed end Calculate the angular speed ω of the minute hand. ω = rad s

Q1(c)

Short Answer 1 mark

During a time interval of 1400 s, the centre of gravity of the piece of modelling clay in Fig. 1.1 moves through a total distance of 0.44 m.

Q1(i)

Short Answer 1 mark

Calculate the angle through which the minute hand moves in this time interval. angle = rad

Q1(ii)

Short Answer 2 marks

Determine distance L. L = m

Q1(iii)

Short Answer 2 marks

Calculate the magnitude of the centripetal acceleration of the piece of modelling clay. centripetal acceleration = m s

Q1(d)

Short Answer 1 mark

Use your answer in (c)(iii) to explain why the variation with time of the magnitude of the force exerted by the minute hand on the piece of modelling clay is negligible as the minute hand undergoes one full revolution. [Total: 10]

Q2(a)

Short Answer 1 mark

(i) Define gravitational potential at a point.

Q2(ii)

Short Answer 2 marks

The Moon may be considered to be an isolated uniform sphere of mass 7.3 × 10 and radius 1.7 × 10 Calculate the gravitational potential at the surface of the Moon. Give a unit with your answer. gravitational potential = unit

Q2(b)

Short Answer 1 mark

An isolated uniform spherical planet has gravitational potential φ at its surface. A particle of mass m is projected vertically upwards from the surface. The particle is given just enough kinetic energy to travel to an infinite distance away from the planet, escaping from the gravitational pull of the planet, without any additional work being done on it.

Q2(i)

Short Answer 1 mark

Determine an expression, in terms of m and φ, for the gravitational potential energy E the particle at the surface of the planet. =

Q2(ii)

Short Answer 2 marks

Show that the speed v at which the particle is projected upwards from the surface of the planet is given byv = -2φ.

Q2(c)

Short Answer 1 mark

A particle is moving upwards at the surface of the Moon. Use your answer in

Q2(c)(ii)

Short Answer 1 mark

to determine the minimum speed of this particle that will result in it escaping from the gravitational pull of the Moon. speed = m s

Q2(d)

Short Answer 3 marks

Hydrogen may be assumed to be an ideal gas. The mass of a hydrogen molecule is 3.34 × 10-27kg. Calculate the root-mean-square (r.m.s.) speed of a hydrogen molecule in hydrogen gas that is at a temperature of 400 K. r.m.s. speed = m s

Q2(e)

Short Answer 1 mark

The surface of the Moon reaches temperatures of approximately 400 K when in direct sunlight. Use your answers in

Q2(e)(d)

Short Answer 1 mark

to suggest a reason why the Moon does not have an atmosphere consisting of hydrogen. [Total: 12]

Q3(a)

Short Answer 1 mark

State what is meant by the internal energy of a system.

Q3(b)

Short Answer 1 mark

Use the first law of thermodynamics to explain what happens to the internal energy:

Q3(i)

Short Answer 1 mark

of a spring when it is stretched at constant temperature within its elastic limit

Q3(ii)

Short Answer 1 mark

of a sample of water when it evaporates from a rain puddle on a hot day. [Total: 8]

Q4

Short Answer 1 mark

An electron in a metal rod moves randomly about a mean position. When an alternating voltage is applied to the ends of the rod, the mean position can be considered to oscillate with simple harmonic motion along the axis of the rod. Fig. 4.1 shows the variation with time t of the displacement x of the mean position from a fixed point on the axis of the rod. 0 0.1 0.2 0.3 0.4 x / 10-15 t / μs

Q4(a)

Short Answer 1 mark

(i) Determine the amplitude of the oscillations. amplitude = m

Q4(ii)

Short Answer 1 mark

Determine the angular frequency of the oscillations. angular frequency = rad s

Q4(iii)

Short Answer 1 mark

Use your answers in

Q4(iii)(ii)

Short Answer 1 mark

to show that the maximum drift speed v of the electron is 1.1 × 10m s

Q4(b)

Short Answer 1 mark

The rod has a cross-sectional area of 4.3 cm and contains a number density of conduction electrons (charge carriers) of 8.5 × 10 All of the conduction electrons in the rod may be assumed to be oscillating in phase with, and with the same amplitude as, the oscillation shown in Fig. 4.1.

Q4(i)

Short Answer 2 marks

Use the information in (a)(iii) to calculate the magnitude I of the maximum current in the rod. = A

Q4(ii)

Short Answer 2 marks

On Fig. 4.2, sketch the variation of the current I in the rod with time t between t = 0 and t = 0.40 μs. 0.1 0.2 0.3 0.4 t / μs

Q4(iii)

Short Answer 1 mark

Use your answers in

Q4(iii)(i)

Short Answer 1 mark

to determine an expression for I in terms of t, where I is in A and t is in s. I =

Q4(iv)

Short Answer 1 mark

Determine the root-mean-square (r.m.s.) current in the rod. r.m.s. current = A [1] [Total: 11]

Q5(a)

Short Answer 1 mark

State Coulomb's law.

Q5(b)

Short Answer 2 marks

Two identical oil droplets are in a vacuum. The centres of the droplets are a distance of 3.8 × 10 m apart. The droplets have equal charge and exert an electric force on each other of magnitude 6.3 × 10-17 Determine the magnitude of the charge on each droplet. charge = C

Q5(c)

Short Answer 1 mark

One of the oil droplets in

Q5(c)(b)

Short Answer 1 mark

is now placed between two horizontal metal plates, as shown in Fig. 5.1. + 1200 V 0 V 5.2 cm metal plates oil droplet Fig. 5.1 (not to scale) A potential difference (p.d.) of 1200 V is applied between the plates, with the top plate at the higher potential. The oil droplet is stationary and in equilibrium.

Q5(i)

Short Answer 1 mark

State the sign of the charge on the oil droplet.

Q5(ii)

Short Answer 3 marks

On Fig. 5.1, draw four lines to represent the electric field between the plates.

Q5(iii)

Short Answer 1 mark

The distance between the plates is 5.2 cm. Determine the mass of the oil droplet. mass = kg [3] [Total: 11]

Q6

Short Answer 1 mark

A capacitor C is charged so that the potential difference (p.d.) V across its terminals is 8.0 V. The capacitor is connected into the circuit of Fig. 6.1. 8.0 V The switch is initially open. The switch is closed at time t = 0.

Q6(a)

Short Answer 1 mark

Fig. 6.2 shows the variation of V with the charge Q on the plates of capacitor C as the capacitor discharges. 0 200 400 600 V / V Q / μC

Q6(i)

Short Answer 2 marks

Show that the energy stored in capacitor C at time t = 0 is 1.8 mJ.

Q6(ii)

Short Answer 2 marks

Determine the capacitance of capacitor C. Give a unit with your answer. capacitance = unit [2] 0 2 1.0 2.0 4 6 8 t / s-ln 8.0 V12

Q6(ii)

Short Answer 1 mark

Determine the time constant τ of the circuit in Fig. 6.1. τ = s

Q6(iii)

Short Answer 1 mark

Calculate the resistance of resistor R. resistance = Ω [2] [Total: 9]

Q7(a)

MCQ 1 mark

A Hall probe containing a thin slice of semiconducting material is placed in a uniform magnetic field of flux density B. The largest faces of the slice are perpendicular to the magnetic field, as shown in Fig. 7.1. semiconducting slice 5.4 A 5.4 A magnetic field, flux density B The thickness x of the slice is 1.8 mm. The number density of charge carriers in the semiconducting material is 1.5 × 10 A constant current of 5.4 A is passed through the slice between the shaded faces. The Hall voltage V that is developed between the terminals PQ is recorded. Fig. 7.2 shows the variation with time t of B. 0 0.02 0.04 0.06 0.08 t / s B / 10

A

Hall probe containing a thin slice of semiconducting material is placed in a uniform magnetic

A

constant current of 5.4 A is passed through the slice between the shaded faces.

B

/ 10

Q7(i)

Short Answer 1 mark

Show that, when B is equal to 4.0 × 10 T, the magnitude of V is 5.0 V.

Q7(ii)

Short Answer 3 marks

On Fig. 7.3, sketch the variation of V with t between t = 0 and t = 0.080 s.- 4 0.02 0.04 0.06 0.08 t / s/ V

Q7(b)

Short Answer 1 mark

The Hall probe in

Q7(b)(a)

Short Answer 1 mark

is replaced with a small flat coil that has 3000 turns. The cross-sectional area of the coil is 3.4 × 10 The plane of the coil is perpendicular to the magnetic field. The electromotive force (e.m.f.) E induced between the terminals of the coil is recorded as B varies as shown in Fig. 7.2.

Q7(i)

Short Answer 3 marks

Show that the magnitude of E at time t = 0.010 s is 2.0 × 10

Q7(ii)

Short Answer 1 mark

On Fig. 7.4, sketch the variation of E with t between t = 0 and t = 0.080 s.- 4 0.02 0.04 0.06 0.08 t / s E / 10 [4] [Total: 11]

Q8(a)

Short Answer 1 mark

State what is meant by a photon.

Q8(b)

Short Answer 1 mark

When the surface of a metal plate is illuminated with electromagnetic radiation, electrons are sometimes emitted from the metal.

Q8(i)

Short Answer 1 mark

State the name of this phenomenon.

Q8(ii)

Short Answer 1 mark

It is observed that this phenomenon occurs only when the frequency of the electromagnetic radiation is greater than a certain minimum value, regardless of the intensity of the radiation. Explain how this observation provides evidence for the existence of photons.

Q8(c)

Short Answer 1 mark

Fig. 8.1 shows the variation of the maximum kinetic energy of the emitted electrons in

Q8(c)(b)

Short Answer 1 mark

with the frequency of the incident radiation. 0 frequency maximum kinetic energy State the name of the quantity represented by:

Q8(i)

Short Answer 1 mark

the gradient of the line in Fig. 8.1

Q8(ii)

Short Answer 1 mark

the y-intercept of the extrapolated line in Fig. 8.1. [Total: 8] 9 Fluorine-18 ( F) is a radioactive nuclide that is used as a tracer in positron emission tomography (PET scanning). Fluorine-18 decays to a nuclide of oxygen (O) according to

Q8(a)

Short Answer 1 mark

(i) State what is meant by a tracer.

Q8(ii)

Short Answer 2 marks

State the symbol of the particle that is represented by X and the values of P, Q and R. X: P: Q: R:

Q8(b)

Short Answer 1 mark

(i) Explain how the radioactive decay of fluorine-18 results in the emission from the body of the gamma-ray photons that are detected during a PET scan.

Q8(ii)

Short Answer 1 mark

Explain how the detection of the gamma-ray photons is used to produce an image of the tissue being examined.

Q8(c)

Short Answer 1 mark

The half-life of fluorine-18 is T. A patient is injected with amount of substance n of fluorine-18.

Q8(i)

Short Answer 3 marks

Determine an expression for the initial value R of the rate R of production of gamma-ray photons by the tracer, in terms of n, T and the Avogadro constant N =

Q8(ii)

Short Answer 1 mark

On Fig. 9.1, sketch the variation with time t of R. [2] [Total: 12]

Q10(a)

Short Answer 1 mark

State Wien's displacement law. Identify any symbols that you use.

Q10(b)

Short Answer 1 mark

A cosmology student observes the electromagnetic radiation received from a star in a galaxy. The student uses Wien's law to estimate the surface temperature of the star, a standard candle to estimate the distance to the galaxy, and the Stefan-Boltzmann law to estimate the radius of the star. The student observes that the radiation from the star is redshifted.

Q10(i)

Short Answer 1 mark

State what is meant by a standard candle.

Q10(ii)

Short Answer 1 mark

State the reason why the radiation from the star is redshifted.

Q10(iii)

Short Answer 1 mark

The true values of the quantities observed or estimated are those that are corrected to allow for redshift. However, the student does not correct for redshift. By placing one tick (3) in each row, complete Table 10.1 to indicate how the observations and estimates made by the student compare with the true values. Table 10.1 student's uncorrected value too low the same too high wavelength of radiation surface temperature of star distance to star radius of star [4] [Total: 8] 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	2023
Session	Oct/Nov
Q&A	72 questions

Physics 2023 · Oct/Nov

Questions & Model Answers 72 Qs

Paper Details