Physics Crash Course MHT-CET>Chapter 22 - Electrons and Photons>Exercise 1>Q 148

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Photoelectric emission is observed from a metallic surface for frequencies $v_{1}$ and $v_{2}$ of the incident light rays $(v_{1} > v_{2}) .$ If the maximum values of kinetic energy of the photoelectrons emitted in the two cases are in the ratio of $1 : K$ then the threshold frequency of the metallic surface is

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Important Questions on Electrons and Photons

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Physics Crash Course MHT-CET>Chapter 22 - Electrons and Photons>Exercise 1>Q 149

When a monochromatic point source of light is at a distance of

0.2 m

from a photoelectric cell, the cut-off voltage and the saturation current are respectively

0.4 V

and

12 mA

. If the same source is placed

0.4 m

away from the photoelectric cell, then

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Physics Crash Course MHT-CET>Chapter 22 - Electrons and Photons>Exercise 1>Q 150

Assertion: Work function of a metal is $4 eV$ . The maximum wavelength of photons required to emit electrons from its surface is about $3100 \overset{\circ}{A}$

Reason: Work function, $ϕ_{0} = hc / λ_{\max}$

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Physics Crash Course MHT-CET>Chapter 22 - Electrons and Photons>Exercise 1>Q 151

In a photoelectric effect, the anode potential is plotted against the plate current
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Physics Crash Course MHT-CET>Chapter 22 - Electrons and Photons>Exercise 1>Q 152

Light of wavelength

3000 \overset{\circ}{A}

falls on sensitive surface. If the surface has received

10^{- 7} J

of energy, then number of photons just falling on the surface are

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Physics Crash Course MHT-CET>Chapter 22 - Electrons and Photons>Exercise 1>Q 154

When a light of wavelength

4000 \overset{°}{A}

falls on a photoelectric emitter, photoelectrons are liberated. For another emitter, the light of wavelength

6000 \overset{°}{A}

is sufficient for photoemission. The work functions of the two emitters are in the ratio of

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Physics Crash Course MHT-CET>Chapter 22 - Electrons and Photons>Exercise 1>Q 155

Special theory of relativity deals with the events in the frames of reference which move with constant

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Physics Crash Course MHT-CET>Chapter 22 - Electrons and Photons>Exercise 1>Q 156

Speed of photons in photoelectric emission is

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Physics Crash Course MHT-CET>Chapter 22 - Electrons and Photons>Exercise 1>Q 157

Photons are not deflected in electric and magnetic field as they are