Tag: physics

Approximately, the temperature corresponding to $1 eV$ translational kinetic energy of molecule is

The work function of a metal is $3.3\times{  10}^{  -19}J$. The maximum wavelength of the photons required to eject electron from the metal is:

A metal plate of area $1\times { 10 }^{ -4 }{ m }^{ 2 }$ is  illuminated by a radiation of intensity 16 m $W/{ m }^{ 2 }.$ The work function of the metal is 5 eV. The energy of the incident photons is 10 eV and only 10% of it produces photo electrons. The number of emitted photo electrons per second and their maximum energy, respectively, will be :
$\left[ { 1eV=1.6\times 10^{ 19 }J } \right] $

The energy of a hydrogen-like atom (or ion ) in its ground state is - 122.4 eV. It may be :

When radiations of wavelength 3000 are incident on a photosensitive surface, the kinetic energy of electrons is 2.5 eV. The stopping potential for 1500 will he,

A photon of energy 12.75 eV is completely absorbed by a hydrogen atom initially in the ground state. The quantum number of the excited state is:

If an $\alpha$-particle is accelerated with the potential V, the energy of $\alpha$-particle will be 

If an $\alpha$-particle and a proton are accelerated from rest by a potential difference of 1 megavolt then the ratio of their kinetic energy will be

A photoelectric surface is illuminated successively by monochromatic light of wavelength $\lambda$ and $\cfrac{\lambda}{2}$. If the maximum kinetic energy of the emitted photoelectrons in the second case is $3$ times that in the first case, the work function of the surface of the material is  ($h=$ Planks constant, $c=$ speed of light)

In photoelectric effect for silver threshold is $\lambda _0 = 3250 \times 10^{-10} m$. If U.V of $\lambda = 2536 \times 10^{-10}$ is incident then velocity of electron from will be