OCR A Level Physics A Unified Physics June 2019 question paper H556/03

A toy rocket is made from a 1.5 litre plastic bottle with fins attached for stability.

The bottle initially contains 0.30 litres of water, leaving 1.2 litres of trapped air at a temperature of 17 °C. A pump is used to increase the pressure of the air within the plastic bottle to 2.4 × 10⁵ Pa at the start of lift-off.

Fig. 1.1 shows the rocket at the start of lift-off.

1 litre = 10^–3 m³

Calculate, in moles, the amount of trapped air in the bottle at the start of lift-off.

The trapped air pushes the water downwards out of the hole, causing the rocket to rise. The temperature of this air remains constant.

Calculate the final pressure of the trapped air just before all the water has been released.

Use the data above to show that the upwards force on the rocket at the start of lift-off is about 15 N.

Hence calculate the initial vertical acceleration of the rocket.

initial acceleration =........ m s^–2

Discuss whether adding more water initially would enable the rocket to reach a greater height.

Complete the nuclear equations for these two processes.

Students want to carry out an investigation into gamma photon absorption using a source of

Explain the shape of the curve in Fig. 3.3.

The torch is inverted 80 times.

Calculate the total energy stored in the capacitor.

At an airport, the conveyor belt for suitcases moves at a constant speed of 1.5 m s^–1. In Fig. 4.1, a suitcase of mass 8.0 kg has reached the line labelled XX'.

Fig. 4.2 shows the situation in vertical cross-section. The frictional force F prevents the suitcase of weight W from sliding to the bottom of the belt. The normal contact force on the suitcase is R. The belt is inclined at an angle of 30° to the horizontal.

Fig. 4.3 shows the suitcase and the forces acting on it at the line labelled YY'.

The centre of mass of the suitcase is now moving at 1.5 m s^–1 along a semi-circular arc of radius 2.0 m.

Calculate the magnitude of the centripetal force acting on the suitcase.

When the suitcase is at line YY', the magnitude of force F is larger and the magnitude of force R is smaller than at XX'.

Explain why this is so.

Hydrogen atoms excited in a discharge tube only emit four different discrete wavelengths of visible photons.

Show that the energy of a photon of wavelength 486 nm is 4.09 × 10^–19 J. (b) (i)

Fig. 5.4 shows some of the energy levels of an electron in a hydrogen atom.

Draw an arrow on Fig. 5.4 to show an electron transition which would cause the emission

of a photon of wavelength 486 nm.

Describe the Doppler effect.

Explain how ultrasound is used to measure the speed of blood flow in an artery.

Use Fig. 6.2 to show that the speed of the loudspeaker is 7.5 m s^–1. (i)

The speed of sound in this experiment is 330 m s^–1. (ii)

Calculate the maximum change in frequency f of the sound detected by the microphone.

Hence complete the scale on the y-axis of Fig. 6.2.

Mark with an X on Fig. 6.1 the position of the loudspeaker which corresponds to the

point X on Fig. 6.2.

In their laboratory notes, one student writes about the accuracy of the measurements whereas the other writes about their precision.

Define these terms.