JEE Previous Year Question

The stopping potential for photoelectrons emitted from a surface illuminated by light of wavelength 6630Å is 0.42 V. If the threshold frequency is x × /s, where x is______(nearest integer).(Given, speed light = 3 x m/s, Planck's constant = 6.63 x Js)

Topic: JEE PYQ

Answer: 35. Full step-by-step solution below.

Correct answer: 35

Solution

(35)
Stopping potential V0 = 0.42 V
= 6630Å
E = + eV0
E: energy of incident photon
V0: Stopping potential
= E - eV0



threshold frequency
1.45 x 1.6 x 10-19 = 6.63 x 10-34x v0
v0 = 0.35 x 1015
= 35 x 1013
= 35

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