GCSE|Edexcel|Physics P1H (Nov 2021)

This question is about ultrasound.

Which of these is a frequency of ultrasound?

• 2.3 Hz

• 23 Hz

• 23 kHz

• 2.3 kHz

Ultrasound has many uses.

One device called a pest repeller emits ultrasound.

The ultrasound keeps mice out of the garden.

Explain why the device affects mice but does not affect humans.

A technician has a different ultrasound device.

This device can emit and detect short pulses of ultrasound.

The device can also measure the time, in ms, from emitting a pulse to

detecting the same pulse.

Describe how the technician can use this device to determine the speed of

ultrasound in air.

Figure 1 shows part of a wave.

Use data from Figure 1 to calculate the wavelength of the wave.

The speed of a water wave is 1.5m/s.

The frequency of the wave is 0.70Hz.

Calculate the wavelength of this wave.

Use the equation: v = f × λ

Water waves are transverse waves.

Describe the difference between transverse waves and longitudinal waves.

This question is about radioactivity.

Alpha (α), beta (β) and gamma (γ) are three types of radioactive emissions.

Which statement describes all of these radioactive emissions?

• ionising and emitted by stable nuclei

• ionising and emitted by unstable nuclei

• neutral and emitted by stable nuclei

• neutral and emitted by unstable nuclei

Fluorine-19 is a stable isotope of the element fluorine.

The element fluorine also has several radioactive isotopes.

Describe one similarity and one difference between the numbers of particles in one nucleus of fluorine-19 and one nucleus of a radioactive isotope of fluorine.

The aluminium sheet is taken away.

The counter is reset to zero and then switched on again.

A new count is taken for 1 minute.

Explain why the new count is greater than 268.