Question

The idea that energy is quantized means

A. energy values must be small

B. energy exists only in discrete amounts

C. Both A and B

In Einstein’s theory, how does a surface electron get the energy to be released from the metal?

A. It interacts with exactly one photon of energy equal or higher than the work function of the metal

B. It interacts with exactly one photon of any energy

A large region of the surface interacts with the light wave, and electrons are freed once enough energy has been transferred to the metal as a whole.

Answer 1

Answer to question 1:

According to photon theory, energy is radiated in the form of energy packets called photons and energy of each photon is given by E= hv , where h is plank's constant and v is frequency of radiation. So, energy radiated is always integral multiple of hv, which means energy exists only in discrete amounts. So option B is correct

Answer to question 2:

Option A is correct, because electrons need at least energy equal to the work function to break free from the metal. Any energy less than that won't be able to free electrons from the metal, and photoelectric effect won't occur.