An electron having a kinetic energy of 100 eV circulates in a path of radius 10 cm in a magnetic field. Find the magnetic field and the number of revolutions per second made by the electron.
Given-
Kinetic energy of an electron = 100 eV
Radius of the circle = 10 cm
We now kinetic energy is given by
Where
From question , we can confer that
Here,
m is the mass of an electron
v is the velocity of an electron.
We know that 1 eV = 1.6 × 10−19 J
Thus,
Now, radius r -
Therefore, magnetic field applied is 3.4 × 10−4 T
Number of revolutions per second of the electron is nothing but the frequency given by ,
From (1)