Question

A metal’s work function is 3.8KJ. Photons strike metal’s surface with an energy of 5.2 KJ. what’s the kinetic energy of the emitted electrons?

(a) 3.8 KJ

(b) 5.2 KJ

(c) 9 KJ

(d) 1.4 KJ

I got this question during an online exam.

The query is from Developments Leading to the Bohr’s Model of Atom in portion Structure of Atom of Chemistry – Class 11

Answer 1

Correct answer is (d) 1.4 KJ

To elaborate: As per the formula of the photoelectric effect, we have E = K.E. + Wo. E is the energy of photons; K.E. is the kinetic energy with which electrons are emitted and Wo is the work function. K.E. = 5.2 KJ – 3.8 KJ = 1.4 KJ.