When the light of frequency (where is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is . When the frequency of the incident radiation is increased to , the maximum velocity of electrons emitted from the sa

STUDY MATERIALS
COURSES
MORE
SUCCESS STORY
ADMISSION
STORE

Back

JEE ADVANCE

CLASS XI - XII
CRASH COURSE

CLASS XI - XII

CRASH COURSE

JEE MAIN

CLASS XI - XII
CRASH COURSE

CLASS XI - XII

CRASH COURSE

NEET

CLASS XI - XII
CRASH COURSE

CLASS XI - XII

CRASH COURSE

BITSAT

CLASS XI - XII

CLASS XI - XII

CBSE BOARD

CLASS IX

CLASS X

CLASS XI

CLASS XII

CLASS VI

CLASS VII

CLASS VIII

UP BOARD

CLASS IX
CLASS X
CLASS XI
CLASS XII

CLASS IX

CLASS X

CLASS XI

CLASS XII

CUET

CRASH COURSE

CRASH COURSE

Courses

CLASSROOM COURSES
ONLINE COURSES

ONLINE COURSES

More

Solution

Q.
When the light of frequency $2 υ_{0}$ (where $υ_{0}$ is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is $v_{1}$ . When the frequency of the incident radiation is increased to $5 υ_{0}$ , the maximum velocity of electrons emitted from the same plate is $v_{2}$ . The ratio of $v_{1}$ to $v_{2}$ is [2018]

1 1 : 2

2 1 : 4

3 4 : 1

4 2 : 1

Ans.
(1)

According to the Einstein’s photoelectric equation,

$E = W_{0} + \frac{1}{2} m v^{2}$

When frequency of incident light is $2 υ_{0}$ .

$h (2 υ_{0}) = h υ_{0} + \frac{1}{2} m v_{1}^{2} \Rightarrow h υ_{0} = \frac{1}{2} m v_{1}^{2}$ ...(i)

When frequency of incident light is $5 υ_{0}$

$h (5 υ_{0}) = h υ_{0} + \frac{1}{2} m v_{2}^{2} \Rightarrow 4 h υ_{0} = \frac{1}{2} m v_{2}^{2}$ ...(ii)

Dividing (i) by (ii), $\frac{1}{4} = \frac{v_{1}^{2}}{v_{2}^{2}} or \frac{v_{1}}{v_{2}} = \frac{1}{2}$

Want Us to Email you About Special Offers & Updates?