Question

Which equation is used to calculate the magnetic force on a charge moving in a magnetic field?

A) F = |q|vBcos
B) F = |q|vBsin
C) F = |q|Bcos
D) F = |q|Bsin

Answer 1

Answer: The correct option is (B).

Step-by-step explanation:

The force on a charge moving in a magnetic field is as follows;

`F= qvBsin\theta`

Here, q is the charge, v is the velocity, B is the magnetic field and
`\theta` is the angle between the velocity and the magnetic field.

The magnetic force is perpendicular to both magnetic field and velocity. Its direction is determined by the right hand rule.

If the angle between the velocity and the magnetic field is 90 degree then the expression of the magnetic force becomes as;

`F= qvB`

Therefore, the correct option is (B).

Answer 2

The force is perpendicular to the plane formed by v and B. Since the force is zero if v is parallel to B, charged particles often follow magnetic field lines rather than cross them.

B) F = |q|vBsin