From the following four cases

PHYSICS · Subjective · CBSE · Physics · Moving Charges and Magnetism · Moving Charges and Magnetism

Problem

From the following four cases, identify the one(s) in which the magnetic force on the charge is minimum. Give a brief reason in each case. (i)

q=+e

v=3\times10^{6}\,\text{m\,s}^{-1}

B=0.30\,\text{T}

\theta=90^{\circ}

(ii)

q=+e

v=3\times10^{6}\,\text{m\,s}^{-1}

B=0.30\,\text{T}

\theta=30^{\circ}

(iii)

q=+e

v=0

B=0.30\,\text{T}

(iv)

q=0

v=5\times10^{6}\,\text{m\,s}^{-1}

B=0.30\,\text{T}