AQA A-Level Physics 2027 Predicted Practice Paper — Paper 2

Answer ALL questions. Write your answers in the spaces provided. You must write down all the stages in your working.

Section A

Short-answer and structured questions. Answer ALL questions.

• 1

  Question SECTION-A1 (6 marks)

  A simple pendulum consists of a small dense bob on a light inextensible string of length 0.850 m, oscillating with small amplitude at a location where g = 9.81 m s^-2. (a) State the condition on the restoring force that must be satisfied for the motion to be simple harmonic. (1 mark) (b) Show that the period of oscillation is approximately 1.85 s. (2 marks) (c) The bob is released from rest with the string displaced 6.0 degrees from the vertical. Calculate the maximum speed of the bob during its motion. State one assumption you make. (3 marks)

  (Total for Question SECTION-A1 is 6 marks)
• 2

  Question SECTION-A2 (7 marks)

  A parallel-plate capacitor of capacitance 220 microfarad is charged to a potential difference of 12.0 V and then, at time t = 0, discharged through a fixed resistor of resistance 47 kilohm. (a) Calculate the energy stored on the capacitor at t = 0. (2 marks) (b) Calculate the time constant of the discharge circuit and state what it represents physically. (2 marks) (c) Determine the potential difference across the capacitor 15 s after discharge begins. (3 marks)

  (Total for Question SECTION-A2 is 7 marks)
• 3

  Question SECTION-A3 (6 marks)

  A geostationary satellite of mass 1200 kg orbits the Earth (mass 5.97 x 10^24 kg, G = 6.67 x 10^-11 N m^2 kg^-2). (a) State two properties of the orbit of a geostationary satellite. (2 marks) (b) Show that the orbital radius of a geostationary satellite is approximately 4.2 x 10^7 m. (3 marks) (c) Calculate the gravitational potential energy of the satellite at this orbital radius. (1 mark)

  (Total for Question SECTION-A3 is 6 marks)
• 4

  Question SECTION-A4 (6 marks)

  A sample of an ideal monatomic gas is contained in a sealed rigid cylinder of volume 2.0 x 10^-3 m^3. The gas exerts a pressure of 1.5 x 10^5 Pa at a temperature of 290 K. (R = 8.31 J mol^-1 K^-1, N_A = 6.02 x 10^23 mol^-1.) (a) Calculate the number of moles of gas in the cylinder. (2 marks) (b) Calculate the total internal energy of the gas. (2 marks) (c) The gas is now heated at constant volume until its pressure doubles. State and explain what happens to the mean kinetic energy of a gas molecule. (2 marks)

  (Total for Question SECTION-A4 is 6 marks)
• 5

  Question SECTION-A5 (7 marks)

  In a nuclear physics experiment a beam of alpha particles is directed at a thin gold foil (the Rutherford scattering experiment). (a) State two observations from this experiment and, for each, the conclusion drawn about the structure of the atom. (4 marks) (b) A single gold-197 nucleus has a radius of about 7.0 x 10^-15 m. Estimate the density of nuclear matter, treating the nucleus as a sphere of mass 197 u where u = 1.66 x 10^-27 kg. (3 marks)

  (Total for Question SECTION-A5 is 7 marks)
• 6

  Question SECTION-A6 (6 marks)

  A student investigates electromagnetic induction using a small circular coil of 250 turns and cross-sectional area 3.2 x 10^-4 m^2 placed in a uniform magnetic field. (a) State Faraday's law and Lenz's law of electromagnetic induction. (2 marks) (b) The coil is initially perpendicular to a field of flux density 85 mT. The field is switched off, falling uniformly to zero in 40 ms. Calculate the mean emf induced in the coil. (3 marks) (c) Explain why no emf would be induced if the plane of the coil were instead kept parallel to the field lines as the field was switched off. (1 mark)

  (Total for Question SECTION-A6 is 6 marks)
• 7

  Question SECTION-A7 (6 marks)

  A radioactive source contains the isotope cobalt-60, which decays by beta-minus emission with a half-life of 5.27 years. A fresh sample has an activity of 3.6 x 10^7 Bq. (a) Write the nuclear equation for the beta-minus decay of cobalt-60 (Z = 27) to an isotope of nickel (Z = 28). Include the antineutrino. (2 marks) (b) Calculate the decay constant of cobalt-60 in s^-1. (2 marks) (c) Calculate the activity of the sample after 12.0 years. (2 marks)

  (Total for Question SECTION-A7 is 6 marks)
• 8

  Question SECTION-A8 (7 marks)

  A charged oil droplet of mass 4.8 x 10^-15 kg is held stationary between two horizontal parallel plates separated by 8.0 mm, with a potential difference of 490 V across them (a Millikan-style arrangement). Take g = 9.81 m s^-2 and e = 1.60 x 10^-19 C. (a) Draw or describe the two forces acting on the stationary droplet and state the condition for it to remain stationary. (2 marks) (b) Calculate the magnitude of the electric field between the plates. (2 marks) (c) Calculate the charge on the droplet and hence the number of excess electrons it carries. (3 marks)

  (Total for Question SECTION-A8 is 7 marks)
• 9

  Question SECTION-A9 (6 marks)

  A mass of 0.60 kg is suspended from a vertical spring of spring constant 24 N m^-1 and set into vertical simple harmonic motion with amplitude 0.050 m. (a) Calculate the frequency of oscillation. (2 marks) (b) Calculate the maximum acceleration of the mass and state where in the motion it occurs. (2 marks) (c) The oscillation is now lightly damped. Sketch-describe how the amplitude varies with time and explain what happens to the total mechanical energy of the system. (2 marks)

  (Total for Question SECTION-A9 is 6 marks)

Section B

Extended response and synoptic questions. Answer ALL questions.

• 1

  Question SECTION-B1 (10 marks)

  A student builds a mass spectrometer to separate ions of two isotopes of magnesium, Mg-24 and Mg-26, which each carry a single positive charge (+e). Singly-charged ions are first accelerated from rest through a potential difference of 2.5 kV, then enter a region of uniform magnetic field of flux density 0.35 T directed perpendicular to their velocity, where they follow semicircular paths before striking a detector. (e = 1.60 x 10^-19 C, u = 1.66 x 10^-27 kg.) (a) Explain why both isotopes gain the same kinetic energy in the accelerating stage but travel at different speeds. (2 marks) (b) Show that the radius of the circular path in the magnetic field is given by r = (1/B)*sqrt(2*m*V/Q), and calculate the radius for the Mg-24 ion. (4 marks) (c) Calculate the separation between the points where the two isotopes strike the detector. (3 marks) (d) State one reason why the magnetic field, rather than an electric field, is used to bend the ion beams into circular paths. (1 mark)

  (Total for Question SECTION-B1 is 10 marks)
• 2

  Question SECTION-B2 (9 marks)

  An engineer models the vertical suspension of a road vehicle as a damped mass-spring system. The sprung mass supported by one wheel is 320 kg and the effective spring stiffness is 3.2 x 10^4 N m^-1. (a) Calculate the natural frequency of undamped vertical oscillation of this mass-spring unit. (2 marks) (b) The car is driven over a road with evenly spaced ridges 1.6 m apart. Determine the speed at which the suspension would be driven at resonance, and explain why this speed is dangerous for the undamped system. (3 marks) (c) The suspension includes a damper. Explain, in terms of energy and amplitude, the effect of adding critical (heavy) damping on the response of the system, and state one advantage and one disadvantage of increasing the degree of damping. (4 marks)

  (Total for Question SECTION-B2 is 9 marks)
• 3

  Question SECTION-B3 (9 marks)

  This question is about a fission reactor and the physics of mass-energy. A nuclear reactor uses the fission of uranium-235. In one representative reaction a U-235 nucleus absorbs a slow neutron and splits, releasing energy of 3.2 x 10^-11 J per fission. (c = 3.00 x 10^8 m s^-1, 1 u = 931.5 MeV, 1 eV = 1.60 x 10^-19 J.) (a) Explain what is meant by binding energy and by binding energy per nucleon, and explain why the fission of a heavy nucleus such as U-235 releases energy. (3 marks) (b) Calculate the loss of mass (mass defect) corresponding to the energy released in one fission event. (2 marks) (c) A reactor delivers 1.8 GW of useful thermal power. Assuming all fission energy appears as thermal power, calculate the number of fission events per second and hence the mass of U-235 consumed per day. Take the mass of one U-235 atom as 3.9 x 10^-25 kg. (4 marks)

  (Total for Question SECTION-B3 is 9 marks)