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A metal has a work function of 3.0 eV. What is the thresh...

A metal has a work function of 3.0 eV. What is the threshold frequency of the metal when electrons are just liberated from the metal.(1 eV = 1.6 × 10-19J; h = 6.6 × 10-34Js)

A.

4.8 × 10-19Hz

B.

9.3 × 10-7Hz

C.

4.8 × 1014Hz

D.

7.3 × 1014Hz

E.

9.3 × 1014Hz

Correct answer is D

The work function (ϕ) of a metal is defined as:

ϕ=hf0

f0=ϕh

ϕ=3.0eV=3.0×1.6×1019

= 4.8×1019J

f0=4.8×10196.6×1034

= 0.727×1015s1

= 7.27×1014s1