Linear spectrum (line spectrum) is a characteristic of which of the following?

What is electromagnetic radiation? How is it produced?

Which of the following sets of radiations cannot be seen in the hydrogen atomic spectrum? $(i)$ $\gamma$-radiation $(ii)$ $UV$ $(iii)$ $X$-rays $(iv)$ Infrared

Mercury street lights emit light of a pale blue color with a wavelength of $436 \, nm$. Calculate its frequency.

According to the electromagnetic theory of Maxwell,what happens when charged particles are accelerated?

Lines of the $Lyman$ series of the spectrum of hydrogen are in