Question

If a proton with velocity v is inside a uniform magnetic field, the work done on the proton by the magnetic field is greater than zero. True OR False

Answer 1

Answer:

ZERO

Explanation:

As we know that force due to magnetic field on moving charge is given by

$\vec F = q(\vec v \times \vec B)$

now here we can say that the force due to magnetic field is always perpendicular to the velocity and it is also perpendicular to the magnetic field.

So we can say that

$\vec F. \vec v = 0$

so power due to magnetic field is always zero

which shows that rate of work done by magnetic field on moving charge is zero

so here the work done by magnetic field is always zero