The energy of an electron in the first Bohr orbit of hydrogen atom is $$-2.18 \times 10^{-18} \mathrm{~J}$$. Its energy in the third Bohr orbit is ____________.

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R :

Assertion A : In the photoelectric effect, the electrons are ejected from the metal surface as soon as the beam of light of frequency greater than threshold frequency strikes the surface.

Reason R : When the photon of any energy strikes an electron in the atom, transfer of energy from the photon to the electron takes place.

In the light of the above statements, choose the most appropriate answer from the options given below :

Henry Moseley studied characteristic X-ray spectra of elements. The graph which represents his observation correctly is

Given $$v=$$ frequency of $$\mathrm{X}$$-ray emitted

Z = atomic number