The electron in the $$\mathrm{n}^{\text {th }}$$ orbit of $$\mathrm{Li}^{2+}$$ is excited to $$(\mathrm{n}+1)$$ orbit using the radiation of energy $$1.47 \times 10^{-17} \mathrm{~J}$$ (as shown in the diagram). The value of $$\mathrm{n}$$ is ___________

Given: $$\mathrm{R}_{\mathrm{H}}=2.18 \times 10^{-18} \mathrm{~J}$$

The number of incorrect statement/s about the black body from the following is __________

(A) Emit or absorb energy in the form of electromagnetic radiation.

(B) Frequency distribution of the emitted radiation depends on temperature.

(C) At a given temperature, intensity vs frequency curve passes through a maximum value.

(D) The maximum of the intensity vs frequency curve is at a higher frequency at higher temperature compared to that at lower temperature.

The number of atomic orbitals from the following having 5 radial nodes is ___________.

$$7 \mathrm{s}, 7 \mathrm{p}, 6 \mathrm{s}, 8 \mathrm{p}, 8 \mathrm{d}$$

The number of following statement/s which is/are incorrect is ___________

(A) Line emission spectra are used to study the electronic structure

(B) The emission spectra of atoms in the gas phase show a continuous spread of wavelength from red to violet

(C) An absorption spectrum is like the photographic negative of an emission spectrum

(D) The element helium was discovered in the sun by spectroscopic method