Question

5.
The kinetic energy of an electron taken from a metal having a work function W = 1.36 eV with
a photon of wavelength 2 = 520 nm, is equal to :
A) 1.2 eV
B) 1.02 eV
C) 0.146 eV
D) 3 eV​

Answer 1

I hope it helps you my friend

Answer 2

Answer:

(B)The kinetic energy of electron is 1.02eV

Explanation:

Given that,

The work function of metal(W)=1.36eV

Wavelength of Photon=520nm

The Energy of photon can be found as follows

$E = \frac{hc}{λ}$

Substituting the known values,we get

$E = \frac{6.626 \times 10 {}^{ - 34} \times 3 \times 10 {}^{8} }{520 \times 10 {}^{ - 9} } \\ = 3.822 \times 10 {}^{ - 19} joule \\ = 3.822 \times 10 {}^{ - 19} \times 6.242 \times 10 {}^{18} ev \\ = 2.38ev$

According to einstein's photoelectric equation,The energy,kinetic energy and work function are related as

$E=W+K.E$

Substituting the known values,we get

$2.38 = 1.36 + K.E \\ = > K.E = 1.02ev$

Therefore,The kinetic energy of electron is 1.02eV

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