When strong magnetic field is applied on a stationary electron, the electron:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → remains stationary.
A magnetic field acts only on a moving charge: the force is \( \vec{F} = q(\vec{v}\times\vec{B}) \). For a stationary electron \( \vec{v} = 0 \), so
\( \vec{F} = q(0\times\vec{B}) = 0 \)
With no force acting, the electron stays where it is, however strong the field is. Along or against the field it could not move in any case, because the magnetic force is never along \( \vec{B} \).
NCERT (2026-27):
Magnetic Field, Lorentz Force – “… (iii) The magnetic force is zero if charge is not moving (as then \( |\mathbf{v}| = 0 \)). Only a moving charge feels the magnetic force.”