An electron (mass = `9.0xx10^(-31)kg` and charge = `1.6xx10^(-19)`coulomb) is moving in a circular orbit in a magnetic field of `1.0xx10^(-4)Wb//m^(2)`. Its period of revolution is _______ .

Options

A. `3.5xx10^(-7)s`
B. `7.0xx10^(-7)s`
C. `1.05xx10^(-6)s`
D. `2.1xx10^(-6)s`

Answer

A

Explanation

`m=9xx10^(-31)kg`
`B=1xx10^(-4)Wb`
`q=1.6xx10^(-19)C`
The periodic time of the motion of electron,
`T=(2pim)/(qB)`
`thereforeT=(2xx3.14xx9xx10^(-31))/(10^(-4)xx1.6xx10^(-19))=3.5xx10^(-7)s`