The curves (1), (2), (3) and (4) show the variation between the applied potential difference (V) and the photoelectric current (i), at two different intensities of light ( I1>I2). In which figure is the correct variation shown?

1. 2.
3. 4.

Subtopic:  Photoelectric Effect: Experiment |
 92%
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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 |
 81%
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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 |
 71%
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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 |
 72%
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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 |
 80%
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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 |
 66%
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A 200 W sodium street lamp emits yellow light of wavelength 0.6 μm. If it is 25% efficient in converting electrical energy to light, how many photons of yellow light does it emit per second?

1. 1.5×1020

2. 6×1018

3. 62×1020

4. 3×1019

Subtopic:  Particle Nature of Light |
 70%
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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 |
 78%
From NCERT
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. 1.00 2. 1.02
3. 1.04 4. 0.98
Subtopic:  Particle Nature of Light |
 73%
From NCERT
AIPMT - 2010
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In an experiment of the photoelectric effect, the wavelength of incident radiation is λ. The wavelength of incident radiation is reduced to 13rd 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 |
 72%
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