Which of the following series of transitions in the spectrum of hydrogen atom falls in the visible region?

Observe the following statements:
Statement-$I$: Rutherford model of an atom cannot explain the stability of an atom.
Statement-$II$: The wavelength of $X$-rays is higher than the wavelength of microwaves.
The correct answer is:

Find the wavelength in the Lyman series for $n_2 = 3$ and $n_1 = 1$.

What is the work function of the metal if the light of wavelength $4000 \, \mathring{A}$ generates photoelectrons of velocity $6 \times 10^5 \, ms^{-1}$ from it? ............. $eV$ (Mass of electron $= 9 \times 10^{-31} \, kg$; Velocity of light $= 3 \times 10^8 \, ms^{-1}$; Planck's constant $= 6.626 \times 10^{-34} \, Js$; Charge of electron $= 1.6 \times 10^{-19} \, C \, eV^{-1}$)

If $\lambda_0$ and $\lambda$ are respectively the threshold wavelength and wavelength of incident light,the velocity of photoelectrons ejected from the metal surface is

If the ratio of the area of two orbits of an $H$ atom is $4 : 1$,then the ratio of the frequency of the $e^-$ in these two orbits is: