Electromagnetic waves transfer energy from a transmitter or source to a receiver or absorber.
Which row in the table correctly identifies both the direction of energy transfer and the order of magnitude of the frequency of the radiation involved?
| Application | Direction of energy transfer | Typical frequency of radiation / Hz\text{Hz}Hz | |
|---|---|---|---|
| A | Medical sterilisation | From a gamma source to bacterial cells | 101110^{11}1011 |
| B | Satellite television | From a ground dish receiver to a broadcasting satellite | 10910^{9}109 |
| C | Thermal imaging | From building walls to an infrared camera | 101310^{13}1013 |
| D | Medical X-ray imaging | From a digital detector to an X-ray tube | 101710^{17}1017 |
A
B
C
D