(a)[3]
Describe how X-rays are used in a security situation. Include a diagram.
(b)[3]
Draw a straight line from each wave to the speed that is most suitable. Radio waves in air Ultrasound in air X-rays in a vacuum Speeds shown: $300\,\text{m s}^{-1}$, $6000\,\text{m s}^{-1}$, $1\times10^{6}\,\text{m s}^{-1}$, $3\times10^{8}\,\text{m s}^{-1}$, $6\times10^{10}\,\text{m s}^{-1}$, $1\times10^{12}\,\text{m s}^{-1}$.