When monochromatic photons of wavelength \(4000~\mathring{A}\) are incident on the metal plate of work function \(2.1~\text{eV},\) what will be the stopping potential for the photocurrent?
1. \(1~\text V\)  2. \(2.1~\text V\) 
3. \(3.1~\text V\)  4. Zero

Subtopic:  Einstein's Photoelectric Equation |
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Level 1: 80%+
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When a point source of monochromatic light is at a distance of \(0.2~\text m\) from a photoelectric cell, the cut-off voltage and saturation current are \(0.6\) volt and \(18~\text{mA}\) respectively. What will happen if the same source is placed \(0.6~\text m\) away from the photoelectric cell?
1. the stopping potential will be \(0.2\) volt.
2. the stopping potential will be \(0.6\) volt.
3. the saturation current will be \(6~\text{mA}.\) 
4. the saturation current will be \(18~\text{mA}.\) 
Subtopic:  Einstein's Photoelectric Equation |
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The correct graph between photoelectric current \((i)\) and intensity \((I)\) is:

1.   2.   
3. 4.  
Subtopic:  Photoelectric Effect: Experiment |
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Level 1: 80%+
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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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Level 1: 80%+
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A \(200~\text{W}\) sodium street lamp emits yellow light of wavelength \(0.6~\mu\text{m}\). If it is \(25\%\) efficient in converting electrical energy to light, how many photons of yellow light does it emit per second?
1. \(1.5\times 10^{20}\)
2. \(6\times 10^{18}\)
3. \(62\times 10^{20}\)
4. \(3\times 10^{19}\)

Subtopic:  Particle Nature of Light |
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Level 2: 60%+
AIPMT - 2012
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A source \(S_1\) is producing, \(10^{15}\) photons per sec of wavelength \(5000~\mathring{A}.\) Another source \(S_2\) is producing \(1.02\times 10^{15}\) photons per second of wavelength \(5100~\mathring{A}.\) Then the ratio of the power of \(S_2\) to the power of \(S_1\) is equal to:
1. \(1.00\) 2. \(1.02\)
3. \(1.04\) 4. \(0.98\)
Subtopic:  Particle Nature of Light |
 76%
Level 2: 60%+
AIPMT - 2010
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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. \(0.25~\mathring{A}\)
2. \(0.5~\mathring{A}\)
3. \(1.5~\mathring{A}\)
4. \(2~\mathring{A}\)

Subtopic:  De-broglie Wavelength |
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An electron is accelerated from rest through a potential difference of \(V\) volt. If the de Broglie wavelength of an electron is \(1.227\times10^{-2}~\text{nm}.\) What will be its potential difference?
1. \(10^{2}~\text{V}\)
2. \(10^{3}~\text{V}\)
3. \(10^{4}~\text{V}\)
4. \(10^{5}~\text{V}\)

Subtopic:  De-broglie Wavelength |
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Level 2: 60%+
NEET - 2020
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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 \((I_1>I_2)\). In which figure is the correct variation shown?
1.    2.
3. 4.
Subtopic:  Photoelectric Effect: Experiment |
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