Which of the following spectral series of the hydrogen atom lies in the visible range of the electromagnetic spectrum?

If $R$ is the Rydberg constant in $cm^{-1}$, then the hydrogen atom does not emit any radiation of wavelength in the range of

The Lyman series of the hydrogen spectrum lies in which region?

$A$ $12.5\; eV$ electron beam is used to bombard gaseous hydrogen at room temperature. What series of wavelengths will be emitted?

For a hydrogen atom,$\lambda_1$ and $\lambda_2$ are the wavelengths corresponding to the transitions $1$ and $2$ respectively,as shown in the figure. The ratio of $\lambda_1$ and $\lambda_2$ is $\frac{x}{32}$. The value of $x$ is $..........$

The first three spectral lines of the $H$-atom in the Balmer series are given as $\lambda_{1}, \lambda_{2}, \lambda_{3}$. Considering the Bohr atomic model,the wavelengths of the first and third spectral lines $\left(\frac{\lambda_{1}}{\lambda_{3}}\right)$ are related by a factor of approximately '$x$' $\times 10^{-1}$. The value of $x$,to the nearest integer,is: