9702_s25_qp_41 | 9702/41/M/J/25 | 9702_s25_qp_43 | 9702/43/M/J/25 | A level Physics | May/June/2025

Описание: 0:00 Introduction 9702/41/M/J/25
00:11 1. (a) Define gravitational potential at a point.
Mars is a planet that may be considered to be an isolated uniform sphere of radius 3.4 × 106 m.
A satellite of mass 122 kg is in orbit around Mars at a constant height of 1.7 × 106 m above the
The height of the orbit is increased to 6.8 × 106 m above the surface. This increases the
gravitational potential energy of the satellite by 5.1 × 108 J.
Show that the mass of Mars is 6.4 × 1023 kg.
6:38 2. A helium atom may be modelled as a nucleus surrounded by two electrons in diametrically opposite circular orbits, each of radius 170 pm, as shown in Fig. 2.1.
(b) (i) State the charge on the nucleus, in terms of the elementary charge e.
3 (a) Define specific latent heat.
Explain why, for a substance, the specific latent heat of vaporisation is usually greater than
the specific latent heat of fusion.
4 (a) (i) State what is meant by the internal energy of a system.
(ii) Explain why the internal energy of an ideal gas is directly proportional to the
thermodynamic temperature of the gas.
5 A cuboidal block floats in a liquid with its base horizontal, as shown in Fig. 5.1.
state three other quantitative conclusions that can be drawn from Fig. 5.2 and Fig. 5.3 about
the block and its oscillations. Use the space for any working.
6 Fig. 6.1 shows a circuit that rectifies an alternating input voltage VIN and produces an output
voltage VOUT across a resistor R.
The four terminals of the rectification circuit are labelled W, X, Y and Z.
A capacitor C is connected in parallel with resistor R.
The variation of VIN with t can be represented by
raw the circuit diagram for the components inside the rectification circuit.
7 (a) Define magnetic flux density.
(b) A particle of mass m and charge +Q moves at speed v into a region where there is a uniform magnetic field, as shown in Figure. 7.1
8 (a) State what is meant by the de Broglie wavelength.
(b) Calculate the de Broglie wavelength of an electron moving at a speed of 4.9 × 107 m s–1
.
(c) State one similarity and one difference between an electron and a positron.
9 (a) Define activity of a radioactive sample. (b) explain why the variation with time of the activity of a radioactive sample is exponential in nature.
(c) A sample contains a single radioactive isotope that decays to form a stable isotope.
The sample has an activity of 180 Bq at time t = 0.
At a time 8.4 minutes later, the activity is 120 Bq.
10 (a) State Hubble’s law. (b) A star in a distant galaxy emits radiation that has a maximum intensity of emission at a
Observations of the galaxy made on the Earth detect the maximum intensity of emission from the star at a wavelength of 4.91 × 10–7 m. Explain why the observed wavelength and the emitted wavelength have different values.