A particle of mass m and charge q is placed at rest in uniform electric field E and then released. The kinetic energy attained by the particle after moving a distance y is

Options

A. qEy
B. `qEy^(2)`
C. `q^(2)Ey`
D. `qE^(2)y`

Answer

A

Explanation

(a): Force acting on a charged particle in a uniform electric field is given by F=qE
Distance travelled = y
Work done by electric force = qEy
According to work-energy theorem, `K_(f) - K_(i) = W_(E) K_(f) - 0 = qEy rArr K_(f) = qEy`