Three identical polaroids $P_1$, $P_2$ and $P_3$ are placed one after another. The pass axis of $P_2$ and $P_3$ are inclined at angle of $60^\circ$ and $90^\circ$ with respect to axis of $P_1$. The source has an intensity $I_0$. The intensity of light finally coming out is

In Young's double slit experiment, two slits are illuminated with a light of wavelength $\lambda$. The line joining $A_1P$ is perpendicular to $A_1A_2$ as shown in figure. If the first minimum is detected at P, the value of slits separation 'a' will be
(D = distance between source and screen)

When a light of wavelength '$\lambda$' falls on the emitter of a photosensitive surface, maximum speed of emitted photoelectrons is 'V'. If the incident wavelength is changed to '$2\lambda/3$', maximum speed of emitted photoelectrons will be

A photoemissive substance is illuminated with a radiation of wavelength $\lambda_i$ so that it releases electrons with de-Broglie wavelength $\lambda_e$. The longest wavelength of radiation that can emit photoelectron is $\lambda_0$. Expression for de-Broglie wavelength is (m = mass of electron, h = Planck's constant, C = Speed of light)