# An electron is accelerated by a potential difference of 12000 volt. It then enters a uniform magnetic field of 10 ^-3 T applied perpendicular to the path of electron .find the radius of the path.Given mass of electron is equal to 9 * 10^-31 kg and charge of electron =1.6*10^-19 C

Grade:12

## 2 Answers

Susmita
425 Points
5 years ago
Say after acceleration final velocity of electron is v.V=12000volt is the potential difference.So kinetic energy of electron is
$\frac{1}{2} mv^2 = eV$
$Or, v= \sqrt {2eV/m}$
Or,v=4.26×1015 m/s
Force on a charged particle in a magnetic field B is
q(vector v×B)=qvBsin(theta)=evBsin90°=evB.

In case velocity is perpendicular to magnetic field,the particle will exhibit circular motion.If r is radius of circular orbit,then centripetal force
$\frac{mv^2}{r} = evB$
$Or, r =\sqrt{\frac{mv}{eB}}$
r=24×105 m.
Susmita
425 Points
5 years ago
It will not be root over in the last line.It was typing mistake.It will be just
r=mv/eB.
Please approve the previous answer if you are helped.

## ASK QUESTION

Get your questions answered by the expert for free