Photons and electrons

Question 1

Frequency

Answer 1

The number of complete waves that pass a point per second. Frequency is measured in hertz (Hz).

Question 2

Wavelength

Answer 2

The distance between two consecutive points on a wave that are in phase.
Wavelength is measured in metres.

Question 3

The photoelectric effect

Answer 3

The process that occurs when light shines on a metal and electrons are ejected.

Question 4

Significance of the photoelectric effect

Answer 4

It establishes the quantum theory and it illustrates the

particle nature of light.

Question 5

A photon

Answer 5

The quantum of energy when the energy is in the form of electromagnetic radiation.

Question 6

Threshold frequency (f0)

Answer 6

The minimum frequency of incident radiation at which electrons will be emitted from a particular metal.

Question 7

Work function of a metal (W0)

Answer 7

The minimum amount of energy needed to emit an electron from the surface of a metal.

Question 8

An absorption spectrum

Answer 8

Produced when white light from a source passes through a “cool” gas. It is also referred to as a line absorption spectrum.

Question 9

An emission spectrum

Answer 9

Produced when electrons “fall” from an orbital of higher energy to an orbital of lower energy. It is also referred to as a line emission spectrum.