Question

A certain metal when irradiated with light
(v = 3.2 x 1016 Hz) emits photo electrons with
twice kinetic energy as did photo electrons
when the same metal is irradiated by light
(frequency= 2.0 * 1016 Hz). Calculate frequency, of electron?
(1) 1.2 x 1014 Hz (2) 8 x 1015 Hz
(3) 1.2 x 1016 Hz (4) 4 x 1012 Hz​

Answer 1

Answer:

ANSWER IS 2 8×1015 Hz

Explanation:

Applying photoelectric equation,

KE=hv−hv0

or (v−v0)=hKE

Given, KE2=2KE1

       v2−v0=hKE2                 ...(i)

and v1−v0=hKE1                 ...(ii)

Dividing equation (i) by equation (ii),

v1−v0v2−v0=KE1KE2=KE12KE1=2

or v2−v0=2v1−2v

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