The maximum number of possible interference maxima for slit-separation equal to twice the wavelength in Young's double-slit experiment, is :

The work function of a substance is $$4.0$$ $$eV.$$ The longest wavelength of light that can cause photo-electron emission from this substance is approximately.

A radiation of energy $$E$$ falls normally on a perfectly reflecting surface. The momentum transferred to the surface is

According to Einstein's photoelectric equation, the plot of the kinetic energy of the emitted photo electrons from a metal $$Vs$$ the frequency, of the incident radiation gives as straight the whose slope