A Level Physics Practice Exam

What phenomenon occurs when electrons in an atom fall from a higher energy level to a lower one?

1. Absorption of energy

2. Emission of photons

3. Ionization

4. Excitation

The correct answer is: Emission of photons

When electrons in an atom transition from a higher energy level to a lower one, they release energy in the form of photons. This process is known as the emission of photons. As an electron drops to a lower energy state, the energy difference between the two levels is released as electromagnetic radiation, which can be observed as light. This phenomenon is fundamental in understanding atomic spectra and is essential in various applications, including lasers and fluorescent lights. The other options pertain to different processes related to electron behavior in atoms. For instance, absorption of energy occurs when an electron moves from a lower energy level to a higher one, which does not describe the situation where electrons fall to a lower state. Ionization involves the complete removal of an electron from an atom, requiring more energy than simple transitions between energy levels. Excitation refers to the process when electrons gain energy and move to a higher state, which is also not relevant to the falling action described.