Which of the following figures represents the variation of the particle momentum and associated de-Broglie wavelength?

A and B are two metals with threshold frequencies 1.8 x 10¹⁴ Hz and 2.2 10¹⁴ Hz. Two identical photons of energy 0.825 eV each are incident on them. Then photoelectrons are emitted by (Take h = 6.6 x 10^-34 J-s)

• B alone

• A alone

• Neither A nor B 

• Both A and B

The emission electron is possible by

• photoelectric effect

• thermionic effect

• both (a) and (b)

• none of the above

An electron and a proton are possessing the same amount of kinetic energies. The de-Broglie wavelength is greater for :

• electron

• proton

• both same

• none of these

If the work function of a metal is 4.2 eV, the cut-off wavelength is :

• 8000 Å

• 7000 Å

• 1472 Å

• 2950 Å

The wavelength of light coming from a distant galaxy is found to be 0.5% greater than the wavelength of light coming from a stationary source. The galaxy is

• coming towards earth with velocity of light

• moving away from earth with velocity 1.5 x 10⁶ m/sec

• stationary with respect to earth

• moving away from earth with velocity of light

Wave nature of light does not explain

• Interference

• Total internal reflection

• Photo-electric effect

• Refraction

The light of frequency v falls on a certain photoelectric substance of threshold  frequency v₀.  The work function of the substance is

• hv₀

• hv

• $\frac{\mathrm{h\gamma }}{{\mathrm{v}}_0}$

• h(v - v₀)

The energy of a photon corresponding to the visible light of maximum wavelength is approximately

• 1 eV

• 1.6 eV

• 3.2 eV

• 7 eV

190.

The rest mass of the photon is

• zero

• infinite

• between zero and infinite

• equal to that of electron