Question

A metal surface is illuminated by a light of given intensity and frequency to cause photo emission. If the intensity of illumination is reduced to one - fourth of its original value, then the maximum $$KE,$$  of emitted photoelectrons will become

A. $${\left( {\frac{1}{{16}}} \right)^{th}}$$  of original value
B. unchanged  
C. twice the original value
D. four times the original value
Answer :   unchanged
Solution :
Maximum $$KE$$  depends on the frequency of incident radiation, not on intensity.

Releted MCQ Question on
Modern Physics >> Dual Nature of Matter and Radiation

Releted Question 1

A particle of mass $$M$$ at rest decays into two particles of masses $${m_1}$$ and $${m_2},$$ having non-zero velocities. The ratio of the de Broglie wavelengths of the particles, $$\frac{{{\lambda _1}}}{{{\lambda _2}}},$$  is

A. $$\frac{{{m_1}}}{{{m_2}}}$$
B. $$\frac{{{m_2}}}{{{m_1}}}$$
C. 1.0
D. $$\frac{{\sqrt {{m_2}} }}{{\sqrt {{m_1}} }}$$
Releted Question 2

A proton has kinetic energy $$E = 100\,keV$$   which is equal to that of a photon. The wavelength of photon is $${\lambda _2}$$ and that of proton is $${\lambda _1}.$$ The ration of $$\frac{{{\lambda _2}}}{{{\lambda _1}}}$$  is proportional to

A. $${E^2}$$
B. $${E^{\frac{1}{2}}}$$
C. $${E^{ - 1}}$$
D. $${E^{ - \frac{1}{2}}}$$
Releted Question 3

A beam of electron is used in an YDSE experiment. The slit width is $$d.$$ When the velocity of electron is increased, then

A. no interference is observed
B. fringe width increases
C. fringe width decreases
D. fringe width remains same
Releted Question 4

Formation of covalent bonds in compounds exhibits

A. wave nature of electron
B. particle nature of electron
C. both wave and particle nature of electron
D. none of these

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