The energy of electromagnetic radiation depends on:

Work function $(W_0)$ values of six metals (in $eV$) are given below: $Li: 2.42, Mg: 3.7, Cu: 4.8, Ag: 4.3, K: 2.25, Na: 2.3$. How many of the above metals do not eject the electrons when they are made to strike with radiation of wavelength $400 \text{ nm}$? $(h = 6.62 \times 10^{-34} \text{ Js})$

The number of the following statements which is/are incorrect is:
$A$. Line emission spectra are used to study the electronic structure.
$B$. The emission spectra of atoms in the gas phase show a continuous spread of wavelength from red to violet.
$C$. An absorption spectrum is like the photographic negative of an emission spectrum.
$D$. The element helium was discovered in the sun by spectroscopic method.

The energy of a radiation of wavelength $8000 \ \mathring{A}$ is $E_1$ and energy of a radiation of wavelength $16000 \ \mathring{A}$ is $E_2$. What is the relation between these two?

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

Alpha rays consist of a stream of