Question

The pictured 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 $7\times {10}^{14}Hz$ strikes the metal surface?

• A. Electrons will be buried deeper within the surface
• B. Electrons will be emitted with negative kinetic energy
• C. A small number of electrons will be emitted with a small amounts of kinetic energy
• D. No electrons will be emitted
• E. The light will only knock loose electrons off the surface of the metal

Answer 1

Answer: (D)

No electrons will be emitted

From figure, the threshold frequency of the metal ${\nu }_{th}=10\times {10}^{14}$ Hz

When light of frequency greater than the threshold frequency of the metal falls on the surface of metal, only then the photoelectrons are emitted. As the light used has frequency less that the threshold frequency of the metal, thus no electrons are emitted.

Hence option D is correct.