Question

5. A particle of mass m and charge q is placed at rest in a uniform electric field E and then
released. The kinetic energy attained by the particle after moving a distance y will be p is
aligned parallel to a uniform electric field E. The work done required to rotate the dipole
by 90° is​

Answer 1

Answer:

Kinetic energy, KE = qEy

Explanation:

It is given that,

The mass of the particle is m having charge q is placed at rest in uniform electric field e and then released.

We have to find the kinetic energy attained by the particle after moving a distance y.

Using third equation of motion as :

Here, u = 0 (particle is initially at rest)

s = y (displacement)

.......(1)

Force on a particle in electric field is, F = qE

Since, F = ma

So, ............(2)

Put the value of a in equation (1)

..................(3)

We know that kinetic energy of a particle is given by,  

Putting equation (3) in above equation.

Ek=3Ey

Hence, this is the required solution.