A 60 W source emits monochromatic light of wavelength 662.5 nm. The number of photons emitted per second is

In an experiment to study photoelectric effect the observed variation of stopping potential with frequency of incident radiation is as shown in the figure. The slope and $$y$$-intercept are respectively

The energy gap of an LED is $$2.4 \mathrm{~eV}$$. When the LED is switched ON, the momentum of the emitted photons is

The kinetic energy of the photoelectrons increases by $$0.52 \mathrm{~eV}$$ when the wavelength of incident light is changed from $$500 \mathrm{~nm}$$ to another wavelength which is approximately