Answer to Question #103170 in Electricity and Magnetism for Ajay

Question

State, giving reasons, whether the following statements are True or False:
(1) An electron moves in a magnetic field of 1T with velocity 5.0 × 10^5
ms^–1
in the direction of
the magnetic field. The magnitude of the force experienced by the electron is 9.5 × 10^–14N.

Answer 1

Solution. A moving electron in a magnetic field is affected by a force whose magnitude is equal to

$$F=qvBsin\alpha$$

where q=1.6 ×*10^-19C is electron charge; v=5.0 × 10^5 ms^–1 is electron speed; B=1T is the magnetic field; α is the angle between the direction of electron velocity and the magnetic field. According to the conditions of the problem

$$\alpha=0$$

Therefore the magnitude of the force is equal to F=0 N. The statement is false.

Answer. False.