The wavelength of an electron and a neutron will become equal when the velocity of the electron is $x$ times the velocity of neutron. The value of $x$ is ____________. (Nearest Integer)

(Mass of electron is $9.1 \times 10^{-31} \mathrm{~kg}$ and mass of neutron is $1.6 \times 10^{-27} \mathrm{~kg}$ )

The maximum number of orbitals which can be identified with $\mathrm{n}=4$ and $m_l=0$ is _________.

The wavelength of an electron of kinetic energy $4.50\times10^{-29}$ J is _________ $\times 10^{-5}$ m. (Nearest integer)

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

$\mathrm{p_x,p_y,p_z,d_{xy},d_{yz},d_{xz},d_{z^2},d_{x^2-y^2}}$

The ionization energy of sodium in $\mathrm{~kJ} \mathrm{~mol}^{-1}$, if electromagnetic radiation of wavelength $242 \mathrm{~nm}$ is just sufficient to ionize sodium atom is _______.

The energy of one mole of photons of radiation of frequency $2 \times 10^{12} \mathrm{~Hz}$ in $\mathrm{J} ~\mathrm{mol}^{-1}$ is ___________. (Nearest integer)

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.

Let a common tangent to the curves ${y^2} = 4x$ and ${(x - 4)^2} + {y^2} = 16$ touch the curves at the points P and Q. Then is equal to __________.

If the wavelength for an electron emitted from $\mathrm{H}$-atom is $3.3 \times 10^{-10} \mathrm{~m}$, then energy absorbed by the electron in its ground state compared to minimum energy required for its escape from the atom, is _________ times. (Nearest integer)

If the work function of a metal is 6.63 $\times$ 10^$-$19J, the maximum wavelength of the photon required to remove a photoelectron from the metal is ____________ nm. (Nearest integer)

[Given : h = 6.63 $\times$ 10 m s]

In the given reaction,

$X+Y+3 Z \leftrightarrows X YZ_{3}$

Wavenumber for a radiation having 5800 $\mathop A\limits^o$ wavelength is $x \times 10 \mathrm{~cm}^{-1}$ The value of is ________. (Integer answer)

Number of spectral lines obtained in $\mathrm{He}^{+}$ spectra, when an electron makes transition from fifth excited state to first excited state will be