AIPMT MAINS2012Physics-Modern Physics

AIPMT MAINS 2012 Physics Photoelectric Effect MCQ Question

Type: MCQ-conceptual-Medium-Class 12

Two radiations of photons energies 1 eV and 2.5 eV, successively illuminate a photosensitive metallic surface of work function 0.5 eV. The ratio of the maximum speeds of the emitted electrons is:

A

1 : 4

B

1 : 2

C

1 : 1

D

1 : 5

Correct Answer

Option B

Detailed Explanation

The kinetic energy of emitted electrons is given by K.E. = E - W. For 1 eV, K.E. = 0.5 eV and for 2.5 eV, K.E. = 2 eV. The ratio of speeds is √(0.5/2) = 1/√4 = 1/2.

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