Question

A solenoid of length $1.0m$ has $100$ turns and as radius $1cm$. $5A$ current is flowing in the solenoid. Calculate the axial magnetic field. If an electron moves along its axis with the velocity ${10}^{4}m/s$, then how much force will it experience?

Answer 1

Length of solenoid $l=10m$
Radius of solenoid $=1cm$, flowing current $I=5A$, Number of turns $N=100$
Axial magnetic field in solenoid
$B={\mu }_0\frac{N}{l}I$
$B=4\pi \times {10}^{-7}\times \frac{100}{1.0}\times 5$
$B=4\times 3.14\times 5\times {10}^{-5}$
$B=6.28\times {10}^{-3}T$ along axial direction
If electron moves with velocity $104m/s$ along its axis, then the angle between magnetic field and velocity will be $0$
From $F=qvB\sin \theta =0(\theta =0^o$)