The force acting on the electron in hydrogen atom (Bohr' theory) is related to the principle quantum number '$$n$$' as

If the frequency of the input voltage is $$50 \mathrm{~Hz}$$, applied to a (a) half wave rectifier and (b) full wave rectifier. The output frequency in both cases is respectively

Periodic time of a satellite revolving above the earth's surface at a height equal to radius of the earth '$$R$$' is [ $$g=$$ acceleration due to gravity]

The wavelength of light for the least energetic photons emitted in the Lyman series of the hydrogen spectrum is nearly [Take $$\mathrm{hc}=1240 ~\mathrm{eV}$$ - $$\mathrm{nm}$$, change in energy of the levels $$=10.2 ~\mathrm{eV}$$ ]