Question

An electron is revolving around a proton producing a magnetic field of $16Wb/m^2$ in circular orbit of radius $1\mathring{A}$. Its angular velocity will be

• A. $10^{17}rad/sec$
• B. $1/2\pi \times 10^{12}rad/sec$
• C. $2\pi \times 10^{12}rad/sec$
• D. $4\pi \times 10^{12}rad/sec$

Answer 1

Answer: (A)

Magnetic field due to revolution of electron
$B=\frac{{\mu }_o}{4\pi }\times \frac{2\pi I}{r}=\frac{{\mu }_o}{4\pi }\times \frac{2\pi }{r}\left(\frac{e\omega }{2\pi }\right)$
$B=10^{-7}\times \frac{e\omega }{r}$
$16=10^{-7}\times \frac{1.6\times 10^{-19}\times \omega }{1\times 10^{-10}}$
$\omega =10^{17}rad/sec$