CBSE
Multiple Choice QuestionsIf the work function of a metal is 4.2 eV, the cut-off wavelength is :
8000 Å
7000 Å
1472 Å
2950 Å
The emission electron is possible by
photoelectric effect
thermionic effect
both (a) and (b)
none of the above
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
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
Wave nature of light does not explain
Interference
Total internal reflection
Photo-electric effect
Refraction
Which of the following has same dimensions to that of Planck's constant?
Work
Energy
Linear momentum
Angular momentum
The rest mass of the photon is
zero
infinite
between zero and infinite
equal to that of electron
The light of frequency v falls on a certain photoelectric substance of threshold frequency v0. The work function of the substance is
hv0
hv
h(v - v0)
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 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
