Question

Given
below are 3 diagrams showing entry
of an electron in a magnatic field
identify the case in which
force on electron will be
(a) maximum
(b) minimum
​

Answer 1

The case in which force on electron will be (a) maximum and (b) minimum will be (i) and (iii) respectively.

• An electron when moves in a magnetic field experience a force on it.
• The magnitude of this force F is given by qVB. Here q, V, and B are the magnitude of the charge, the velocity, and the magnitude of the magnetic field in which the electron is traveling.
• This force is maximum when all q, V, and B are mutually perpendicular to each other.
• In case (i) the electron is traveling perpendicular to the field and in case (iii) it is traveling parallel to the field.
• Hence the force is maximum and minimum on the electron in each case.

Answer 2

Explanation:

a) force of electron in fig 1 is maximum because here the direction of of the motion of current is at the right angles to that lf of magnetic field b

b) force of electron in fig 3 is minimum because here the electron is moving in a same direction along with magnetic field b