Dual Nature of ...

A monochromatic source of light operating at 200 W emits $$4 \times 10^{20}$$ photons/second. Then the wavelength of light used is

The de-Broglie wavelength of a bus moving with speed 'v' is $$'\lambda'$$ .Some passengers left the bus at a stoppage . Now when the bus moves with twice its initial speed, its kinetic energy is found to be twice its initial value. The de-Broglie wavelength now is

If the momentum of an electron is changed by $$p_{m}$$, then the de Broglie wavelength associated with it increased by $$0.5\%$$. The initial momentum of electron will be

The momentum of a photon of a electromagnetic radiation is $$3.3\times 10^{-29}kg \ m \ s^{-1}$$ .The frequency of the associated waves is $$(h = 6.6 \times 10^{-34} Js, c = 3 \times 10^{8} m/s)$$ 

Light of wavelength $$5000 A^o$$ falls on a sensitive surface. If the surface has received $$10^{-7}J$$ of energy, then the number of photons incident on the surface is nearly (given $$h= 6.6 \times 10^{-34}$$ Js $$c = 3 \times 10^{8}$$ m/s)

A positron and a proton are accelerated by the same accelerating potential. Then the ratio of the associated wavelengths of the positron and the proton will be :
[ $$M$$ = Mass of proton, $$m$$ = Mass of positron]

Electrons are accelerated through a p.d. of 150V. Given $$ m=9.1\times{10}^{-31} $$ Js, the de Broglie wavelength associated with it is 

The de Broglie wavelength associated with an electron of energy 500 eV is given by

The wavelength of de broglie waves associated with a beam of protons of kinetic energy $$5 \times 10^{2}$$eV.
(Mass of each photon$$= 1.67 \times 10^{-27}$$Kg, $$h=6.62 \times 10^{-34}$$Js.)

The momentum ( in Kg-m/s) of an electron having wavelength 2$$A^{0}$$  $$(h=6.62 \times10^{-34}Js.)$$