Question

what is meant by line emission and line absorbtion spectrum

Answer 1

Line Absorption - the characteristic pattern of dark lines or bands that occurs when electromagnetic radiation is passed through an absorbing medium into a spectroscope. An equivalent pattern occurs as coloured lines or bands in the emission spectrum of that medium.

Line Emission - The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to an atom or molecule making a transition from a high energy state to a lower energy state.