Q. An electric field of 1500 Vm$^{-1}$ and a magnetic field of 0.40 Wbm$^{-2}$ act on a moving electron. The minimum uniform speed along a straight line the electron could have is
A) $1.6 \times \ 10^{15}\ {ms}^{- 1}$
B) $6 \times 10^{16}{ms}^{- 1}$
C) $3.75 \times 10^{3}{ms}^{- 1}$
D) $3.75 \times 10^{2}{ms}^{- 1}$
Explanation
(c) Here, $E = 1500\ {Vm}^{- 1},\ B = 0.4\ {Wbm}^{- 2}$
Minimum speed of electron along the straight line
$v = \frac{E}{B} = \frac{1500}{0.4} = 3750$
$\ = \ 3.75\ \times 10^{3}\ {ms}^{- 1}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.