If wavelength of the first line of the Paschen series of hydrogen atom is $720 \mathrm{nm}$, then the wavelength of the second line of this series is _______ $\mathrm{nm}$. (Nearest integer)

Following figure shows spectrum of an ideal black body at four different temperatures. The number of correct statement/s from the following is _______.

A. T₄ > T₃ > T₂ > T₁
 B. The black body consists of particles performing simple harmonic motion.
 C. The peak of the spectrum shifts to shorter wavelength as temperature increases.
 D. $\frac{{\mathrm{T}}_1}{{\mathrm{\nu }}_1} = \frac{{\mathrm{T}}_2}{{\mathrm{\nu }}_2} = \frac{{\mathrm{T}}_3}{{\mathrm{\nu }}_3}$
 E. The given spectrum could be explained using quantisation of energy

The number of given orbitals which have electron density along the axis is

${\mathrm{p}}_{\mathrm{x}},{\mathrm{p}}_{\mathrm{y}},{\mathrm{p}}_{\mathrm{z}},{\mathrm{d}}_{\mathrm{xy}},{\mathrm{d}}_{\mathrm{yz}},{\mathrm{d}}_{\mathrm{xz}},{\mathrm{d}}_{\mathrm{z}}^2,{\mathrm{d}}_{{\mathrm{x}}^2-{\mathrm{y}}^2}$