caesium has a work function of 3 x 10-19J. the maximum energy of liberated electrons...

JAMB 2008

caesium has a work function of 3 x 10-19J. the maximum energy of liberated electrons when it is illuminated by light of frequency 6.7 x 1014

HZ is?

[h = 6.6 x 1010-34Js]

A. 1.42 x 10^-19J
B. 3.00 x 10^-19J
C. 4.42 x 1010^-19J
D. 7.42 x 10^-19J

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Correct Answer: Option A

Explanation

Max kinetic energy = Energy of incident electron - work function. EK = hf - w
= 6.6 x 10-34 x 6.7 x 1014 - 3 x 10-19
= 4.422 x 10-19 - 3 x 10-19
= 1.422 x 10-19J

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