Answer to Question #89698 in Electricity and Magnetism for Khadeeja

Question

A particle of mass 0.5g carries a charge of 2.5× 10^-8C. The particle is given an initial velocity of 6 ×10^4 ms^-1. To keep the particle moving in a horizontal direction,
(A) the magnetic field should be perpendicular to the direction of the velocity
(B)the magnetic field should be along the direction of velocity
(C)magnetic field should have a minimum value of 3.27 T
(D) no magnetic field is required Out of the above statements,
(1)only A is true
(2)only B is true
(3)only A and C are true
(4)only B and C are true
(5)Only D is true

Answer 1

The gravitational force will try to deflect the particle from its horizontal path. If magnetic field acting perpendicular to initial velocity going into paper, it will exert a force on particle in a direction opposite to gravitational force.

In this case, we can write

$$qBv=mg (1)$$

Using (1) we get

$$B=\frac {mg}{qv} (2)$$

B=3.27 T

Answer:

(3)only A and C are true