A microwave transmitter is positioned a fixed distance away from a flat reflecting surface, as illustrated. A microwave detector is then moved at a constant speed along a straight path from $X$ to $Y$. A sequence of intensity maxima and minima is recorded. The separation between neighbouring maxima is $1.5\,\text{cm}$. What is the frequency of the microwave radiation?
- A$1.0 \times 10^{8}\,\text{Hz}$
- B$2.0 \times 10^{8}\,\text{Hz}$
- C$1.0 \times 10^{10}\,\text{Hz}$
- D$2.0 \times 10^{10}\,\text{Hz}$