Question

The graph shows the relationship between the maximum kinetic energy of electrons flying off the surface of a metal versus the frequency of light striking the metal surface as part of the photoelectric effect. According to this graph, what will happen when light of frequency $6\times {10}^{14}\text{Hz}$ strikes the metal surface?

• A. No electrons will be emitted.
• B. Small number of electrons will be emitted.
• C. Electrons will be emitted with negative kinetic energy.
• D. The light will only knock the loose electrons off the surface of metal.

Answer 1

The correct option is A No electrons will be emitted.

From figure, the threshold frequency of the metal,

${\nu }_{threshold}=10\times {10}^{14}\text{Hz}$

When light of frequency greater than the threshold frequency of the metal falls on the surface of the metal, only then the photoelectrons are emitted.

As the light used has frequency, $\nu (6\times {10}^{14})<{\nu }_{threshold}$ .

Thus, no electrons are emitted.

Hence, option $\left(D\right)$ is correct.