Question

The threshold frequency of zinc for the photoelectric effect is found to lie in the ultraviolet range. Identify which of the following statement is true if X-rays are shined on a zinc metal surface?

• A. No electrons will be emitted from the metal.
• B. Electrons will be released from the metal but have no kinetic energy.
• C. Electrons will be released from the metal and have kinetic energy.
• D. Elections will be released from the metal but will immediately be recaptured by the zinc atoms.
• E. Electrons will simply move from one zinc atom in the metal to another zinc atom in the metal

Answer 1

The correct option is C Electrons will be released from the metal and have kinetic energy.

Note: X-rays have higher frequency than UV rays.

It is mentioned that the threshold frequency of zinc lies in the ultraviolet region $\Rightarrow$ for zinc to emit electrons it needs light having at least the frequency of UV.

Here X-rays are used therefore the electrons are emitted but the remaining energy of X-rays is used up in giving kinetic energy to the emitted electrons.

Thus option C is correct.