The ratio of centripetal acceleration for an electron revolving in the $3^{\text{rd}}$ orbit to the $5^{\text{th}}$ Bohr orbit of a hydrogen atom is:

When an electron falls from a higher energy level to a lower energy level,the difference in energy is emitted as electromagnetic radiation. Why can it not be emitted as other forms of energy?

An electron is revolving in a circular orbit of radius '$r$' in a hydrogen atom. Using Bohr's theory, the angular momentum of the electron is (where '$M$' = magnetic dipole moment,'$m$' = mass of electron,'$e$' = charge of electron).

The ratio of the speed of the electron in the first Bohr orbit of hydrogen and the speed of light is equal to (where $e, h$ and $c$ have their usual meanings).

Would the Bohr formula for the $H-$ atom remain unchanged if the proton had a charge of $+ \frac{4e}{3}$ and the electron a charge of $- \frac{3e}{4}$ (where $e = 1.6 \times 10^{-19} \ C$)? Give reasons for your answer.

In Bohr's model of the hydrogen atom,let $PE$ represent potential energy and $TE$ represent total energy. When an electron transitions to a higher energy level,