(a)[1]
Fig. 7.1 shows the initial letter of some colours in the visible section of the spectrum. State which colours are absent.
(b(i))[1]
State the names of the regions of the electromagnetic spectrum used for communications.
(b(ii))[1]
State the name of the region of the electromagnetic spectrum used in remote controls for televisions and DVD players.
(c)[1]
Describe how large amounts of microwave energy can be dangerous to people.
(d)[2]
State two safety precautions that must be taken when using X-rays.