Question

Kinetic energy of photoelectrons in two different experiments of photoelectric effect were found in the ratio of 2:1. If the frequencies of these radiations were v1 and v2 , then what should be the threshold frequency? Options are: 1) 2v2-v1 2) v2-v1 3) v2-2v1 4) v1-3v2 Please explain clearly...

Answer 1

Answer:This may help you

Explanation:

The Einstein's equation for photoelectric effect is given by , KE=hν−hν0

​where KE=maximum kinetic energy of electron, h= Planck's constant , ν0

= threshold frequency and ν= frequency of incident light .

Also KE= 1/2mv^2

where v= maximum velocity of electron.

In first case,

1/2mv^2 1

​=h(2ν0)−hν0=hν0 ....(1) and

In second case,

1/2mv^2 2=h(5ν0)−hν0 =4hν0....(2)

From (1) and (2),

1/2mv^2 2=4×1/2mv^2

​or v2

​=2v1 =2×(4×10^6)

=8×10^6m/s.