Radiation Safety Practice Exam

How are the energy levels of gamma rays and X-rays measured?

1. By mass

2. By energy output

3. By frequency

4. By wavelength

The correct answer is: By frequency

The energy levels of gamma rays and X-rays are measured by their frequency. This is based on the principles of quantum mechanics and the relationship established by Planck's equation, which states that energy is directly proportional to frequency. Specifically, the energy (E) of a photon can be calculated using the formula E = hν, where h is Planck's constant and ν (nu) is the frequency of the radiation. Higher frequency corresponds to higher energy levels, which is why gamma rays, having much higher frequencies compared to X-rays, possess greater energy. This principle is crucial in radiation safety, as the higher the energy, the more penetrating ability a photon has, influencing how radiation interacts with matter and biological tissues. While wavelength is also related to energy (as they are inversely proportional), measuring energy strictly by frequency provides a more direct understanding of the radiation's potential effects and interactions. Therefore, frequency is the most appropriate measure of the energy levels of gamma rays and X-rays.