(a(i))[1]
One section of the electromagnetic spectrum in Fig. 7.1 has not been labelled. Give the name of this section.
(a(ii))[1]
Give a suitable value for the speed of infra-red waves in a vacuum.
(a(iii))[1]
Some sections of the electromagnetic spectrum have wavelengths shorter than visible light. Give one example.
(b(i))[2]
X-rays and γ-rays are used in hospitals. Describe one medical use for X-rays and one use for γ-rays.
(b(ii))[2]
Explain why γ-rays are dangerous to living things.