(a)[2]
State two ways in which progressive waves and stationary waves differ.
(b(i))[3]
A source $S$ of microwaves is positioned in front of a metal reflector $R$, as shown in Fig. 6.1. A microwave detector $D$ is placed between $R$ and $S$. Describe how stationary waves are formed between $R$ and $S$.
(b(ii))[2]
Describe how $D$ is used to demonstrate that stationary waves are formed between $R$ and $S$.
(b(iii))[2]
Describe how the wavelength of the microwaves can be determined with the apparatus in Fig. 6.1.
(c)[3]
In (b), the microwave wavelength is $2.8\text{ cm}$. Calculate the frequency, in GHz, of the microwaves.