CLASS XII - Physics
Milikan performed an experiment
for the verification of Einstein photoelectric equation.
For this he
subjected the group IA metal over light with suitable frequency. The apparatus
was set up as shown in figure. He kept a wheel W with metal coated over it and
a knife K was kept so that the metal surface could be kept clean and shining.
When the
potential was decreased to minimum such that photoelectric current was 0. Then,
that potential is known as stopping potential. It is denoted by VS.
Then,
From photoelectric equation,
Here,
h is plank's Constant, f is the frequency of light or photon, f0 is the threshold
frequency & e is the charge of the electron.
The is the equation of straight
line in the form y = mx +c. Hence, Einstein photoelectric equation is correct.
Then, we know that,
In this way, Plank's Constant is
determined.
Comments
Post a Comment