Question

An electron with velocity 3 * 10^7 ms-1 describes a circular path in a uniform megnatic field of 0.2t, perpendicular to it. calculate the radius of path.

Answer 1

ma=F

mv²/R=qvBsinα

circular path = >sinα = 90⁰

q=e= 1.6•10⁻¹⁹ C,

m=9.1•10⁻³¹ kg

R=mv/eB =

=9.1•10⁻³¹•3•10⁷/1.6•10⁻¹⁹•0.2 =

Answer 2

r=$\frac{mv}{qB}$

on putting all the values we can get

r = 85.31×$10^{-5}$