AQA A Level Physics Paper 1 June 2022 question paper 7408/1

Two stable isotopes of helium are 42He and 32He.

An atom of 42He is produced in a rock that contains uranium. It is produced following 238 the radioactive decay of a 92U atom. The decay also creates an atom of thorium (Th).

238 Write an equation for the decay of 92U.

238

A 32He nucleus can be produced by the decay of a tritium nucleus 31H.

State and explain which exchange particle is responsible for this decay.

Helium was discovered by analysing the light in the absorption spectrum of the Sun.

Figure 1 shows the positions of the brightest lines, labelled A to F, in the emission spectrum of helium. The brightest lines in the emission spectra of sodium and hydrogen are also shown.

Before helium was identified, some scientists suggested that the lines of the helium spectrum seen in the absorption spectrum of the Sun were due to the presence of sodium and hydrogen.

Discuss, with reference to the lines A to F in Figure 1, the evidence for and against this suggestion.

Calculate, in eV, the change in energy level responsible for the spectral line labelled in Figure 1.

Explain, with reference to the processes within an atom, the difference between an emission spectrum and an absorption spectrum.

Carbon-14 d ys into nitrogen-14 with the release of a beta (β⁻) particle and an

State the change of quark character in β⁻ decay.

Figure 2 shows the distribution of kinetic energies of β⁻ particles from the decay of carbon-14.

Explain how Figure 2 supports the existence of the antineutrino.

The existence of the antineutrino was confirmed by experiments in which antineutrinos interact with protons. The equation for this interaction is:

Identify particle X.

The positron released in this interaction is annihilated when it encounters an electron. A pair of gamma photons is then produced. Particle X can be absorbed by a nucleus. This produces another gamma ray. Table 1 contains data for three gamma photons detected during an antineutrino–proton interaction experiment.

Deduce which of the three gamma photons could have been produced by positron annihilation.

Figure 3 shows a garden gate with a pulley system designed to close the gate.

The pulley system raises weight A when the gate is opened. When the gate is released, A falls. The horizontal cable C passes over pulley R. The tension in cable C causes the gate to close.

Weight A is a solid cylinder with the following properties:

length = 0.23 m weight = 35 N

Table 2 gives the density of three available materials.

Deduce which one of the three materials is used for A.

Figure 4 shows the pulley arrangement when the gate is closed.

Pulleys P and M are frictionless so that the tension in the rope attached to A is equal to the weight of A. A weighs 35 N and the weight of moveable pulley M is negligible.

Calculate the tension in the horizontal cable C when the gate is closed.

Pulley M is pulled to the left as the gate is opened.

Explain why this increases the tension in the horizontal cable C.

Figure 5 shows a plan view with the gate open. The horizontal cable C passes over pulley R and is attached to the door at D. The angle between the door and the horizontal cable C is 12°.

The horizontal distance between the hinge and D is 0.95 m.

The tension in the horizontal cable C is now 41 N.

Calculate the moment of the tension about the hinge.

The same system is attached to an identical gate with stiffer hinges. Now the system does not supply a sufficiently large moment to close the gate.

Discuss two independent changes to the design to increase the moment about the hinges due to horizontal cable C.

A student assembles the circuit in Figure 6.

The battery has an internal resistance of 2.5 Ω.

Show that the resistance of the 6.2 V, 4.5 W lamp at its working potential difference (pd) is about 9 Ω.

The terminal pd across the battery is 6.2 V.

Calculate the emf of the battery.

The student makes a variable resistor to control the brightness of the lamp.

Figure 7 shows her circuit.

She uses a resistance wire with a diameter of 0.19 mm to make the variable resistor. A 5.0 m length of this wire has a resistance of 9.0 Ω.

Calculate the resistivity of the wire.

Figure 8 shows the 5.0 m length of wire wrapped around a tube to make the variable resistor.

Two plugs connect the variable resistor into the circuit. A moveable copper contact is used to vary the length of wire in series with the lamp. When the contact is placed on the tube at one particular position, the lamp is dim. The contact is then moved slowly to the right as shown in Figure 8.

Explain, without calculation, what happens to the brightness of the lamp as the contact is moved.

The student now makes a different circuit by connecting the variable resistor in parallel with the lamp.

The contact is returned to its original position on the tube as shown in Figure 8 and the lamp is dim. The contact is again slowly moved to the right.

Explain, without calculation, what happens to the brightness of the lamp as the contact is moved.

A teacher sets up a demonstration to show the relationship between circular motion and simple harmonic motion (SHM). She places a block on a turntable at a point 0.25 m from its centre, as shown in Figure 9.

The turntable rotates with an angular speed of 1.8 rad s^–1 and the block does not slip.

Calculate the time taken for the turntable to complete one revolution.

Figure 10 shows a plan view of the turntable and block. The turntable rotates in a clockwise direction.

Draw an arrow on Figure 10 to show the direction of the resultant force on the block.

The mass of the block is 0.12 kg.

Calculate the magnitude of the resultant force on the block.

Describe, with reference to one of Newton’s laws of motion, the evidence that a resultant force is acting on the block.

The teacher adjusts the angular speed of the turntable so that the block completes one rotation every 2.50 s. She sets up a simple pendulum above the centre of the turntable so that it swings in phase with the movement of the block.

Calculate the length of the simple pendulum.

A lamp is used to project shadow images of the block and pendulum bob on a screen. Both shadows appear to move with SHM across the screen. Figure 11 shows the images on the screen at one instant.

Initially the shadows move in phase with the same amplitude.

Air resistance affects the motion of the pendulum.

Suggest the effect this has on the amplitude relationship and the phase relationship between the moving shadows.

Two transparent prisms A and B of different refractive indices are placed in contact to produce a rectangular block. Figure 12 shows the path of a ray, incident normally on A, refracting as it crosses the boundary between the prisms.

Explain how the path of the ray shows that the refractive index of A is greater than the refractive index of B.

Show that the angle of refraction of the ray in B is about 60°.

Draw, on Figure 12, the path of the ray immediately after it reaches P. Justify your answer with calculations.

Section B

Each of Questions 07 to 31 is followed by four responses, A, B, C and D.

For each question select the best response.

Which two quantities have the base unit kg m² s⁻²?

Which gives SI prefixes in descending order of magnitude?

A car travels at 100 km h⁻¹ on a motorway.

What is an estimate of its kinetic energy?

What is the specific charge of a 136 C nucleus?

Which row describes the variation with distance of the strong nuclear force?

Which statement is correct?

Which combination of quarks is possible?

In photoelectricity, V_s is the stopping potential.

A fluorescent tube contains a gas.

The coating of the tube

Which row gives evidence for the wave nature of electrons and evidence for the particulate

Which particle has the smallest de Broglie wavelength?

A longitudinal wave of frequency 660 Hz travels through a medium.

Which statement describes the motion of a particle in the wave?

The frequency of the first harmonic of a standing wave on a string is f. The tension in the string is T. The tension is increased to 4 T without changing the length or mass of the string.

Which harmonic has a frequency 2 f after this change?

Light of wavelength 5.2 × 10⁻⁷ m is used in a Young’s double-slit experiment. The distance from the slits to the screen is 1.5 m. The width of ten fringes is 3.5 cm.

What is the separation of the two slits?

Monochromatic light of wavelength 5.8 × 10⁻⁷ m is incident normally on a plane transmission diffraction grating that has a slit separation of 2.5 × 10⁻⁶ m.

How many maxima are produced by the grating?

An aeroplane flies horizontally at 150 m s⁻¹ along a bearing 60° east of north.

How far north from its starting position is the aeroplane after one hour?

A ball is thrown vertically upwards and returns to its original position 2.4 s later. The effect of air resistance is negligible.

What is the total distance travelled by the ball?

A truck of mass 2.1 × 10³ kg tows a car of mass 1.3 × 10³ kg along a horizontal road. The total resistive force on the car is 1100 N. The acceleration of the car and truck is 2.3 m s⁻².

What is the tension in the tow rope?

A parachutist descends to the ground at a constant speed with the parachute open.

Which force, together with the parachutist’s weight, makes a pair according to Newton’s third law of motion?

A tennis ball has a mass of 58 g. The ball is dropped from rest from a height of 1.8 m above the ground and falls vertically. The ball rebounds vertically to a height of 1.1 m. The effect of air resistance is negligible.

What is the change in momentum of the ball during its collision with the ground?

A mass M is suspended from a spring. When the mass is at rest at the equilibrium position, the elastic potential energy stored is E. An extra mass of 2 M is added to the spring and the spring extends while still obeying Hooke’s law.

What is the total elastic energy stored when the system is at rest at the new equilibrium

Two wires P and Q are made of the same material and have the same cross-sectional area. P has an original length L and is subject to a tensile force F. P extends a distance x. Q has an original length 2 L and is subject to a tensile force 2 F.

Which statement is correct?

The current in a metallic conductor is 1.5 mA.

How many electrons pass a point in the conductor in two minutes?

Which value of resistance cannot be made by combining three 10 Ω resistors?

A particle performs simple harmonic motion with a time period of 1.4 s and an amplitude of 12 mm.

What is the maximum speed of the particle?