# <!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> When monochromatic photons of wavelength $$4000$$ Å are incident on the metal plate of work function $$2.1$$ eV, what will be the stopping potential for the photocurrent? 1.  $$1$$ V 2.  $$2.1$$ V 3.  $$3.1$$ V 4. Zero

Subtopic:  Einstein's Photoelectric Equation |
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When a point source of monochromatic light is at a distance of 0.2 m from a photoelectric cell, the cut-off voltage and saturation current are 0.6 volts and 18 mA respectively. What will happen if the same source is placed 0.6 m away from the photoelectric cell?

 1 the stopping potential will be 0.2 volts. 2 the stopping potential will be 0.6 volts. 3 the saturation current will be 6 mA. 4 the saturation current will be 18 mA.

Subtopic:  Einstein's Photoelectric Equation |
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The variation of the kinetic energy $$(K)$$ of photoelectrons as a function of the frequency $$(f)$$ of the incident radiation is best shown by:

 1 2 3 4
Subtopic:  Einstein's Photoelectric Equation |
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The correct graph between the maximum energy of a photoelectron $$\left(K_{max}\right)$$ and the inverse of the wavelength $$\left(\frac{1}{\lambda}\right)$$ of the incident radiation is given by the curve:

 1 $$A$$ 2 $$B$$ 3 $$C$$ 4 None of these
Subtopic:  Einstein's Photoelectric Equation |
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If alpha, beta and gamma rays carry the same momentum, which has the longest wavelength?

 1 Alpha rays 2 Beta rays 3 Gamma rays 4 None, all have same wavelength
Subtopic:  De-broglie Wavelength |
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A 200 W sodium street lamp emits yellow light of wavelength 0.6 $\mathrm{\mu m}$. If it is 25% efficient in converting electrical energy to light, how many photons of yellow light does it emit per second?

1. $1.5×{10}^{20}$

2. $6×{10}^{18}$

3. $62×{10}^{20}$

4. $3×{10}^{19}$

Subtopic:  Particle Nature of Light |
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AIPMT - 2012
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Electrons used in an electron microscope are accelerated by a voltage of 25 kV. If the voltage were increased to 100 kV, then the de-Broglie wavelength associated with the electrons would:
 1 decrease by 2 times 2 decrease by 4 times 3 increase by 4 times 4 increase by 2 times

Subtopic:  De-broglie Wavelength |
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AIPMT - 2011
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A source S1 is producing, 1015 photons per sec of wavelength 5000 Å. Another source S2 is producing 1.02×1015 photons per second of wavelength 5100 Å. Then the ratio of the power of S2 to the power of S1 is equal to:

 1 1 2 1.02 3 1.04 4 0.98
Subtopic:  Particle Nature of Light |
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AIPMT - 2010
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In an experiment of the photoelectric effect, the wavelength of incident radiation is $\lambda$. The wavelength of incident radiation is reduced to $\frac{1}{3}$rd of initial value and the maximum kinetic energy of photoelectron is observed to be n times the previous value. What will be the threshold wavelength for the metal plate?
1. $$\frac{n-1}{n-3} \lambda$$
2. $$\frac{n}{n-3} \lambda$$
3. $$\frac{n-3}{n-1} \lambda$$
4. $$\frac{n+1}{n-3} \lambda$$

Subtopic:  Einstein's Photoelectric Equation |
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The de-Broglie wavelength of a particle accelerated by a 150 volt potential difference is 10-10 m. What will its wavelength be if it is accelerated by a 600 volt potential difference?

1. 0.25 $\stackrel{o}{A}$

2. 0.5 $\stackrel{o}{A}$

3. 1.5 $\stackrel{o}{A}$

4. 2 $\stackrel{o}{A}$

Subtopic:  De-broglie Wavelength |
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