OCR A Level Physics A Modelling Physics June 2025 question paper H556/01

Which of these physical constants requires the greatest number of different base SI units?

A Avogadro constant, N_A

B Boltzmann constant, k

C Gravitational constant, G

D Molar gas constant, R

A metal block of mass m is at temperature T₀. An electrical heater of constant power P heats the block for time t and it reaches a temperature T₁. The overall efficiency of the process is x.

Which expression gives the correct value of c, specific heat capacity of the block?

A light rod is hung from a horizontal ceiling using 2 springs, one attached to each end. The springs have force constants k and 2 k.

A downwards force F is applied closer to one end of the rod such that the rod is horizontal.

What is the tension T in the spring with the force constant 2 k ?

A material is heated so that it changes state from solid to liquid and after further heating changes to gas.

Which of the following properties of the particles have increased?

1 Mean kinetic energy 2 Order 3 Spacing

A 1 and 3 only

B 1, 2 and 3

C 2 and 3 only

D 3 only

The apparent position of a star changes by an angle of 1.0 × 10^{– 4} degrees between observations made 6 months apart from the same place on Earth.

What is the distance of the star from Earth in parsecs?

A 2.8

B 5.6

C 170

D 330

A washing machine with a circular drum of diameter 0.60 m is rotating at an angular velocity of 15 radians per second.

What is the magnitude of the force exerted by the drum on a 0.30 kg item of clothing which is at the bottom of the spinning drum?

A 21 N

B 23 N

C 41 N

D 43 N

Which of the following determines whether a super red giant evolves to a black hole?

A Dark matter

B Electron degeneracy

C Mass of the core

D The Chandrasekhar limit

Monochromatic light of wavelength 600 nm is passed through a diffraction grating.

Maxima are formed on a screen 3.0 m from the grating. The distance between the two first order maxima, on either side of the zero maximum, is 1.42 m.

What is the spacing, in m, between lines on the diffraction grating?

1.3 × 10^{– 6} A

1.4 × 10^{– 6} B

2.5 × 10^{– 6} C

2.6 × 10^{– 6} D

Which option correctly gives the likely evolution of the Sun?

The surface temperature of the Sun is 5800 K and the peak wavelength is 500 nm.

What is the surface temperature, in K, of the star represented by the graph below?

A body moves with simple harmonic motion. Which graph shows the correct relationship between its period, T, and its amplitude, A ?

Which of these statements about the Universe is implied by the Cosmological principle?

A Dark energy is found in every galaxy

B Kepler’s laws can be applied to any solar system

C Matter and anti-matter were formed in the very early Universe

D Microwave background radiation corresponds to a temperature of 2.7 K

An electric car of mass 1700 kg is tested to measure its maximum speed.

Fig. 16.1 shows a graph of velocity v against time t for the first 18 seconds of the test.

During this time the force produced by the motor is constant.

Fig. 16.1

Describe using Fig. 16.1, the method you would use to estimate the distance travelled in 18 s.

Use the graph in Fig. 16.1 to show that the acceleration of the car at time t = 12 s is about 1.5 m s^–2.

Use Fig. 16.1 to calculate the change of momentum of the car in 18 s.

=........ kg m s^–1

Fig. 16.2 shows a graph of resultant force against time during the test.

Fig. 16.2

Explain, in terms of the forces acting on the car, the shape of the graph in Fig. 16.2.

Explain why the value you have calculated in (a)(iii) is the area under the graph in Fig. 16.2.

The diagram below shows one of the wheels of the car that is driven by the electric motor.

Use Newton’s third law to explain how frictional forces cause the car to accelerate.

Calculate the resultant force acting on the car at t = 12 s, using your answer to (a)(ii).

An aircraft is flying horizontally at an altitude of 10 000 m and a constant speed of 220 m s^–1. 17

While maintaining this speed, the controls are adjusted so that the aircraft is in projectile motion until the altitude is 7500 m.

Throughout the projectile motion the passengers experience apparent weightlessness.

A condition for projectile motion is constant vertical acceleration. State the other condition.

Show that t, the time taken to reach the new altitude of 7500 m, is about 23 s.

Determine the magnitude and direction of the velocity of the aircraft at time t.

velocity =........ m s

angle to the vertical........

Explain why the engines of the aircraft must provide thrust during the projectile motion.

Explain why the passengers are described as ‘weightless’ during the projectile motion of the aircraft.

Part of a machine to generate electrical energy using waves is a cylindrical drum whose cross-section is shown below. The height of the drum is 2.0 m and its cross-sectional area is 0.79 m².

The mass of the drum is 1200 kg.

The centre of mass of the drum is 0.50 m from one of the circular faces, on a line joining the centres of the circular faces.

The density of water is 1000 kg m^–3.

The drum floats in flat water with its long axis vertical. The base of the drum is a distance d below the surface, where d is measured in m.

Explain why the weight of water displaced must be equal to the weight of the drum.

Calculate d.

Upthrust forces act at the centre of mass of the fluid displaced.

Explain why the drum cannot float in equilibrium on its side with the long axis horizontal.

When the vertical drum is displaced a distance x deeper into the water from the equilibrium position, the magnitude of the resultant force on the drum, F, is given by

F = –kx

where k is a constant and d is measured in m.

By considering the magnitude of the additional upthrust on the drum, show that k is about 8000 Nm^–1.

When the drum is released, it oscillates vertically. Explain why the oscillations are simple harmonic motion.

Calculate the natural frequency f of the oscillations.

* Two designs, A and B, of the machine are tested in a large ripple tank.

The ripple tank can produce waves whose amplitude and frequency can be varied over wide ranges.

The natural frequencies of the two machines are identical. The graphs show the results of the tests but are incomplete.

• Describe how the amplitude of the machine could be measured at each frequency tested. You do not need to describe how to vary the amplitude or frequency of the waves.

• Complete the graphs with suitable labels and annotations.

• Discuss which of the designs is the most effective at generating electrical energy.

Additional space if required

State why thermal energy passes into the tank.

Explain, in terms of particle energies, why the temperature of the oxygen remains constant despite the transfer of thermal energy into the tank.

Show that in one hour the volume of liquid oxygen that evaporates is about 0.02 m³. (c)

After one hour the number of moles of gas above the remaining liquid oxygen is 710.

Calculate the pressure of the gas.

Plot the missing data point on the graph above and draw a line of best fit.

Describe the relationship suggested by the graph and suggest an explanation.

21* Analysis of stellar light can identify the elements that are present in the outer layers of a star.

Absorption spectra of visible light collected from two main sequence stars, Vega and Tau Ceti, are shown below. The spectra were collected by a telescope orbiting the Earth. The dark lines on the diagram show wavelengths where the intensity was zero or close to zero.

• Explain the cause of the dark lines.

• Describe and explain at least one difference between the spectra.

• Analyse the spectra to determine which star is older.

Additional space if required

An asteroid of mass 10 kg is in a circular orbit around the Sun at a distance of 3.5 AU from the centre of the Sun.

1 AU = 1.5 × 10¹¹ m

Use Kepler’s third law to calculate the period of the orbit of the asteroid in years.

An object orbiting the Sun at a distance of 1 AU has a period of 1 year.

Calculate the kinetic energy of the asteroid.

Use the graph to calculate the change in gravitational potential energy of the satellite from the moment of collision until it crosses the Earth’s orbit.

Eventually, the asteroid falls into a new orbit around the Sun. This orbit is elliptical.

State the other feature of this orbit predicted by Kepler’s first law.

Calculate the magnitude of the recession velocity of M87.

velocity =........ km s^–1

Estimate the distance in light years to M87 using Hubble’s law.

Hubbles constant H_o = 2.5 × 10^–19 s^–1

Estimate the percentage uncertainty in the distance calculated in part (b) using the width of the emission line in the diagram.

percentage uncertainty = +/–........ %

Other methods have shown M87 is actually 50 million light years from Earth.

Suggest why M87 might contradict Hubble’s law.

Suggest one reason why the Big Bang theory is still the accepted model of the origin of the Universe.