Ejection of the photoelectron from metal in the photoelectric effect experiment can be stopped by applying $0.5\, V$ when the radiation of $250\, nm$ is used. The work function of the metal is ................ $eV$

Explain the importance and the main postulates of Planck's quantum theory.

What is the shortest wavelength in the $Pfund$ series of $He^{+}$ ion?

How did Niels Bohr obtain detailed information regarding the structure of atoms and molecules?

$A$ metal surface is illuminated by light of two different wavelengths $248 \ nm$ and $310 \ nm$. The maximum speeds of the photoelectrons corresponding to these wavelengths are $u_1$ and $u_2$ respectively. If the ratio $u_1 : u_2 = 2 : 1$ and $hc = 1240 \ eV \ nm$,the work function of the metal is nearly $:-$ (in $eV$)

Explain the phenomenon of black body radiation.