Question

An electron is projected along the axis of solenoid, the trajectory of electron shall be

(1) Circular path 

(2) Uniform motion along the axis 

(3) Uniform accelerated motion in straight line 

(4) Parabolic path

Answer 1

Correct Option is (2) Uniform motion along the axis

\(\overrightarrow{F} =q(\overrightarrow{V}\times \overrightarrow{B})\) 

\(\because\) \(\overrightarrow{V} || \overrightarrow{B} \) 

\(\therefore\) \(\overrightarrow{F}=0\) 

And magnetic force can never do work

\(\Rightarrow\) Straight line and uniform motion