Question

Light of wavelength 3500 Å is incident on two metals A and B. Which metal will yield more photoelectrons if their work functions are 5 eV and 2 eV respectively?

(a) A

(b) B

(c) A & B

(d) C

This question was posed to me in a job interview.

The query is from PhotoElectric Effect topic in division Quantum Physics of Engineering Physics I

Answer 1

Correct answer is (b) B

Explanation: Here, λ = 3500 Å = 3.5 X 10^-7m

Energy of incident photons = hv = \(\frac{hc}{\lambda}\)

= 3.536 eV

Since the work function of metal A is higher, it will not yield any photoelectrons. Hence, only metal B will yield photoelectrons.