Heat treatment of muscular pain involves radiation of wavelength of about 900 nm. Which spectral line of H atom is suitable for this purpose?

[R_H = 1 $$ \times $$ 10⁵ cm^–1, h = 6.6 $$ \times $$ 10^–34 Js, c = 3 $$ \times $$ 10⁸ ms^–1]

The ground state energy of hydrogen atom is – 13.6 eV. The energy of second excited state of He⁺ ion in eV is :

Which of the graphs shown below does not represent the relationship between incident light and the electron ejected from metal surface ?

Which of the following combination of statements is true regarding the interpretation of the atomic orbitals ?

(a) An electron in an orbital of high angular momentum stays away from the nucleus than an electron in the orbital of lower angular momentum.

(b) For a given value of the principal quantum number, the size of the orbit is inversely proportional to the azimuthal quantum number.

(c) According to wave mechanics, the ground state angular momentum is equal to $${h \over {2\pi }}$$.

(d) The plot of $$\psi $$ vs r for various azimuthal quantum numbers, shows peak shifting towards higher r value.