Question

According to classical electromagnetic theory, the electron revolving around a proton in hydrogen atom in an orbit of radius $5.3\times 10^{-11}m$ with velocity $2.2\times 10^{6}m{s}^{-1}$ is

• A. does not emit any radiation
• B. emits radiation of any frequency
• C. emits frequency of light of $6.6\times 10^{15}Hz$
• D. emits frequency of light of $2.2\times 10^{15}Hz$

Answer 1

Answer: (C)

The frequency of the electron moving around the proton is
$v=\frac{v}{2\pi r}=\frac{2.2\times 10^{6}m{s}^{-1}}{2\pi \left(5.3\times 10^{-11}m\right)}\approx 6.6\times 10^{15}Hz$
According to the classical electromagnetic theory, we know that the frequency of the electromagnetic waves emitted by the revolving electrons is equal to the frequency of its revolution around the nucleus. Thus, the initial frequency of the light emitted is $6.6\times 10^{15}Hz$.