5.2 Electromagnetic Waves

Figure 7

When the prongs of the tuning fork are struck, the prongs vibrate in the directions shown by the arrows on Figure 7.

Describe how the vibrating tuning fork causes a sound wave to travel through the air.

You may add to the diagram if it helps your answer.

The following descriptions describe waves from different parts of the electromagnetic spectrum.

Complete each description by adding the name of the wave.

Use the name of each wave only once. Each description refers to a different part of the electromagnetic spectrum.

Description 1

used in cooking

used in short-range communication

typical wavelength 900 nm

name of wave ..................................................

Description 2

used in cooking

used in communication

typical wavelength 150 mm

name of wave ...............................................

Description 3

used in communication

produced by oscillations in electrical circuits

typical wavelength 150 m

name of wave .............................................

Description 4

used in medical scanning

is emitted by the nucleus of an atom

typical wavelength 2.0 × 10⁻³ nm

name of wave ..............................................

Higher Only

When white light crosses the boundary between air and glass, it can split up into the colours of the spectrum.

Explain, in terms of speed, why the light behaves like this.

Visible light travels at a speed of 3.00 × 10⁸ m/s in a vacuum.

State the speed with which gamma radiation travels through space.

Table 1 shows an incomplete list of the electromagnetic spectrum.

Table 1

Higher Tier Only

Figure 1

Describe the interaction between the X-rays and 

People who work with X-rays need to take precautions to keep themselves safe.

Suggest one way that workers can keep themselves safe when working with X-rays.

Figure 1 shows a radio wave. Each 1 cm square is equal to 2 m.

Figure 1

Calculate the wavelength of this radio wave.

The speed of light in a vacuum is 3.00 × 10⁸ m/s

   A   Gamma, X-ray, microwave

   B   Microwaves, visible light, radio waves

   C   Microwaves, infrared, ultraviolet

   D   Ultraviolet, microwaves, radio waves

   A   Used to send communication signals

   B   Used to treat cancerous tumours

   C   Used to take images of bones through the skin

   D   Used for cooking

An optical fibre is inserted into a patient's body to examine the liver during keyhole surgery.

Explain why visible light is more useful and safer than X-rays during this surgery.