Question

Atomic spectrum should be :
A. Pure line spectrum
B. Emission band spectrum
C. Absorption line spectrum
D. Absorption band spectrum

Answer 1

Hint: The magnetic field and electric field exist in the electromagnetic wave and light is also an EM wave and the direction of propagation of light and oscillations of magnetic field particles and electric field particles are mutually perpendicular. Light is the example for continuous spectrum.

Complete answer:
Basically there are two ways to excite the atom. Usually all the substances in the world tend to stay at the lower energy level. Same idea is valid for the electrons too. The electrons always stay in the ground state. When they are hit by some other atoms i.e collided with other atoms or when they absorb photons from the light, they get excited. When they get excited, they go to higher energy levels. They can't stay there because their nature is to attain the least energy state. So they come back to ground state by emitting some radiation. Those are spectral lines and they have both dark and bright lines. We can use these spectral lines to identify the elements. Because various atoms produce various colors of spectral lines. Hence it is called a pure line spectrum.

So option A is the correct answer.

Note:
The reason why we discussed light is, light contains radiations of continuous different wavelengths. That is the continuous spectrum. But the emission spectra from atoms contains spectral lines i.e dark and bright lines. Dark in the sense some wavelength is missing over there. Hence we call it a discontinuous spectrum. Even when energy is absorbed by an electron, then also we will get one spectrum called the absorption spectrum.