Continuous spectrum is not produced by which of the following?

$A$ neutron moving with a speed $v$ makes a head-on collision with a stationary hydrogen atom in its ground state. The minimum kinetic energy of the neutron for which an inelastic collision will take place is....$eV$

If elements with principal quantum number $n > 4$ were not allowed in nature,then the number of possible elements would be

Continuous emission spectrum is produced by

$A$ beam of ultraviolet light of all wavelengths passes through hydrogen gas at room temperature,in the $x-$ direction. Assume that all photons emitted due to electron transition inside the gas emerge in the $y-$ direction. Let $A$ and $B$ denote the lights emerging from the gas in the $x$ and $y$ directions respectively.

The wavelength of the emission line spectrum and the absorption line spectrum of a substance are related as: