The energy of the second Bohr’s orbit of the hydrogen atom is -328 kJ mol${}^{-1}^\{-1\}$. The energy of fourth Bohr’s orbit would be

The threshold frequency of a metal is $1\times 10^{15}{s}^{-1}1\; \backslash times\; 10^\{15\}\backslash ,s^\{-1\}$. The ratio of maximum kinetic energies of the photoelectrons when the metal is irradiated with radiations of frequencies $1.5\times 10^{15}{s}^{-1}1.5\; \backslash times\; 10^\{15\}\; s^\{-1\}$ and $2.0\times 10^{15}{s}^{-1}2.0\; \backslash times\; 10^\{15\}\; s^\{-1\}$ respectively, would be

The threshold frequency of a metal ‘M’ is $1.5\times 10^{15}{s}^{-1}1.5\; \backslash times\; 10^\{15\}\; s^\{-1\}$. The maximum K.E. of the photoelectrons, when the metal is irradiated with radiations of frequency $2.5\times 10^{15}{s}^{-1}2.5\; \backslash times\; 10^\{15\}\; s^\{-1\}$, would be

The de-Broglie wavelength associated with a body of mass 1000g moving with a velocity 100 $m{s}^{-1}ms^\{-1\}$ is

The H-specturm shows

Correct set of four quantum numbers for the valence (outermost) electron of rubidium (Z = 37) is

The principal quantum number of an orbital is related to the

Which one of the following sets of quantum numbers represents an impossible arrangement?

Which of the following has the maximum number of unpaired electrons?

The number of nodal planes in a $p_{x}p\_x$ orbital is