Photoelectric Effect and Wave Theory of Light

Author:NCERT
12th CBSE
IMPORTANT

Important Questions on Photoelectric Effect and Wave Theory of Light

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A particle A with a mass mA is moving with a velocity v and hits a particle B (mass mB) at rest (one dimensional motion). Find the change in the de Broglie wavelength of the particle A. Treat the collision as elastic.

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Consider a metal exposed to light of wavelength 600 nm. The maximum energy of the electron doubles when light of wavelength 400 nm is used. Find the work function in eV.

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Consider figure for photoemission.

How would you reconcile with momentum-conservation? Note light (photons) have momentum in a different direction than the emitted electrons.
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There are two sources of light, each emitting with a power of 100 W. One emits X-rays of wavelength 1 nm and the other visible light at 500 nm. Find the ratio of number of photons of X-rays to the photons of visible light of the given wavelength?

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Do all the electrons that absorb a photon come out as photoelectrons?

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There are materials which absorb photons of shorter wavelength and emit photons of longer wavelength. Can there be stable substances which absorb photons of larger wavelength and emit light of shorter wavelength.

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A particle moves in a closed orbit around the origin, due to a force which is directed towards the origin. The de Broglie wavelength of the particle varies cyclically between two values λ1,λ2 with λ1>λ2 . Which of the following statement are true?

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Photons absorbed in matter are converted to heat. A source emitting n photon per second of frequency ν is used to convert 1 kg of ice at 0oC to water at 0oC. Then, the time T taken for the conversion : 

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The de Broglie wavelength of a photon is twice the de Broglie wavelength of an electron. The speed of the electron is ve=C100. Then

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Two particles A1 and A2 of masses m1, m2(m1>m2) have the same de - Broglie wavelength. Then

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Relativistic corrections become necessary when the expression for the kinetic energy 12mv2, becomes comparable with mc2, where m is the mass of the particle. At what de Broglie wavelength will relativistic corrections become important for an electron?

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An electron (mass m) with an initial velocity v=v0i^ is in an electric field E=E0j^. If, λ0=hmv0, it's de-Borglie wavelength at time t is given by

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An electron (mass m) with an initial velocity V=v0i ^ , (v0>0) is in an electric field E=-E0i^ (E0=constant >0).It's de Broglie wavelength at time t is given by

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An electron is moving with an initial velocity v=voi^ and is in a magnetic field B=Boj^. Then it's de Broglie wavelength

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A proton, a neutron, an electron and an α-particle have same energy. Then their de Broglie wavelengths compare as

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The wavelength of a photon needed to remove a proton from a nucleus which is bound to the nucleus with 1 MeV energy is nearly

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A particle is dropped from a height H. The de Broglie wavelength of the particle as a function of height is proportional to