Question

In an orbit of radius $0.4A^0$ an electron revolves with a frequency of $6.25\times {10}^{15}$ Hz. The magnetic induction field at its centre is (in Tesla):

• A. $4\pi$
• B. $2\pi$
• C. 4
• D. 2

Answer 1

The correct option is A $4\pi$

Revolution per second $=6.25\times {10}^{15}$

$⟹$ Total current=$6.25\times {10}^{15}\times 1.6\times {10}^{-19}={10}^{-3}A$

Magnetic induction $B=\frac{{\mu }_{0}i}{2r}=4\pi \times {10}^7\times {10}^{-7}=4\pi T$