A light of intensity $$12 \mathrm{Wm}^{-2}$$ incidents on a black surface of area $$4 \mathrm{~cm}^2$$. The radiation pressure on the surface is
The electric field $$(E)$$ and magnetic field $$(B)$$ of an electromagnetic wave passing through vacuum are given by
$$\begin{aligned} & E=E_0 \sin (k x-\omega t) \\ & B=B_0 \sin (k x-\omega t) \end{aligned}$$
Then the correct statement among the following is
In a photoelectric experiment light of wavelength 800 nm produces photoelectrons with the smallest de-Broglie wavelength of 1 nm . Light of 400 nm produces photoelectrons with smallest de-Broglie wavelength of 0.5 nm. Then the work function of the metal used in the experiment is nearly.
A hydrogen atom at the ground level absorbs a photon and is excited n = 4 level. The potential energy of the electron in the excited state is