Photoelectric Effect

The photoelectric equation is given by:

h%20f%20%3D%20h%20f_0%20%2B%20K_%7B%5Ctext%7Bmax%7D%7D

where: -

h

is Planckâ€™s constant (

6.6%20%5Ctimes%2010%5E%7B-34%7D

Js), -

f

is the incident frequency (

1.0%20%5Ctimes%2010%5E%7B15%7D

Hz), -

f_0

is the threshold frequency, -

K_%7B%5Ctext%7Bmax%7D%7D

is the maximum kinetic energy of emitted electrons (

2%20%5Ctimes%2010%5E%7B-19%7D

J). 1. Rearrange the equation for

f_0

f_0%20%3D%20%5Cfrac%7Bh%20f%20-%20K_%7B%5Ctext%7Bmax%7D%7D%7D%7Bh%7D

2. Substituting the values:

f_0%20%3D%20%5Cfrac%7B(6.6%20%5Ctimes%2010%5E%7B-34%7D%20%5Ctimes%201.0%20%5Ctimes%2010%5E%7B15%7D)%20-%20(2%20%5Ctimes%2010%5E%7B-19%7D)%7D%7B6.6%20%5Ctimes%2010%5E%7B-34%7D%7D

%3D%20%5Cfrac%7B6.6%20%5Ctimes%2010%5E%7B-19%7D%20-%202%20%5Ctimes%2010%5E%7B-19%7D%7D%7B6.6%20%5Ctimes%2010%5E%7B-34%7D%7D

%3D%20%5Cfrac%7B4.6%20%5Ctimes%2010%5E%7B-19%7D%7D%7B6.6%20%5Ctimes%2010%5E%7B-34%7D%7D

%3D%206.97%20%5Ctimes%2010%5E%7B14%7D%20%5Ctext%7B%20Hz%7D

Thus, the correct answer is

%5Cboxed%7B6.97%20%5Ctimes%2010%5E%7B14%7D%20%5Ctext%7B%20Hz%7D%7D

Chapter Questions
1 MCQs