A photon of energy $E$ strikes a photosensitive material with negligible work function. An emitted photoelectron has a de Broglie wavelength $\lambda_d$. If the mass of the photoelectron is $m$, which of the following expresses the relationship between $E$ and $\lambda_d$?

Light of wavelength $\lambda$ strikes a photo-sensitive surface and electrons are ejected with kinetic energy $E.$ If the kinetic energy is to be increased to $2E,$ the wavelength must be changed to $\lambda '$ where

The energy of a photon of light of wavelength $450\;nm$ is

What determines the hardness of the $X$-rays obtained from the coolidge tube

When photons of energy $hv$ fall on an aluminium plate (of work function $= {E_0}$), photoelectrons of maximum kinetic energy $K$ are ejected. If the frequency of the radiation is doubled, the maximum kinetic energy of the ejected photoelectrons will be

The filament current in the electron gun of a coolidge tube is increased while the potential difference used to accelerate the electrons is decreased. As a result, in the emitted radiation

The stopping potential for photoelectrons emitted from a metal surface illuminated by light of wavelength $\lambda$ is $V_0$. If the wavelength is reduced to $\lambda/2$, keeping the intensity constant, the new stopping potential will be:

The work function of metal is $1\;eV.$ Light of wavelength $3000\;\mathop A\limits^ \circ$ is incident on this metal surface. The velocity of emitted photo-electrons will be

The material used for making thermionic cathode must have

The wavelength of the photoelectric threshold for silver is ${\lambda _0}.$ The energy of the electron ejected from the surface of silver by an incident light of wavelength $\lambda (\lambda < {\lambda _0})$ will be

A photon of energy $E$ ejects a photoelectrons from a metal surface whose work function is ${W_0}.$ If this electron enters into a uniform magnetic field of induction $B$ in a direction perpendicular to the field and describes a circular path of radius $r,$ then the radius $r,$ is given by, (in the usual notation)