A beam of light has three wavelengths, ,

PHYSICS · Subjective · A Level · Physics · Particles and radiation · Particles and radiation

Problem

A beam of light has three wavelengths,

4144\,\text{\AA}

4972\,\text{\AA}

, and

6216\,\text{\AA}

, with a total intensity of

3.6\times10^{-3}\,\text{W m}^{-2}

equally distributed amongst the three wavelengths. The beam falls normally on an area of

1.0\,\text{cm}^2

of a clean metallic surface of work function

2.3\,\text{eV}

. Assume that there is no loss of light by reflection and that each energetically capable photon ejects one electron. Calculate the number of photoelectrons liberated in two seconds.

Related theory

Quantum Explanation of PE
Einstein's Photoelectric Equation
Photoelectric effect
Dual Nature of Radiation and Matter
The photoelectric effect

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