Speed of an electron in Bohr's $7^{\text{th}}$ orbit for Hydrogen atom is $3.6 \times 10^6\,m/s$. The corresponding speed of the electron in $3^{\text{rd}}$ orbit,in $m/s$ is $........\times 10^6$.

In which of the following systems will the radius of the first orbit $(n = 1)$ be minimum?

In Bohr's theory of the hydrogen atom,'$r$' is the radius of the orbit,'$V$' is the speed of the electron, and '$E$' is the total energy of the electron. Which of the following physical quantities is inversely proportional to the principal quantum number '$n$'?

The de Broglie wavelength of the electron in the ground state is $\lambda_1$ and that in the $n = 3$ level is $\lambda_3$. Then $\lambda_3$ is given by:

According to de Broglie,if the wavelength of an electron in the second orbit is $10^{-9} \ m$,then the circumference of the orbit is .......

If an electron in a hydrogen atom jumps from the third orbit to the second orbit,the frequency of the emitted radiation is given by (where $c$ is the speed of light and $R$ is the Rydberg constant):