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Q. No.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
| 1. | decrease by \(2\) times |
| 2. | decrease by \(4\) times |
| 3. | increase by \(4\) times |
| 4. | increase by \(2\) times |
Subtopic: De-broglie Wavelength |
80%
Level 1: 80%+
AIPMT - 2011
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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 |
77%
Level 2: 60%+
AIPMT - 2010
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In an experiment of the photoelectric effect, the wavelength of incident radiation is . The wavelength of incident radiation is reduced to 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. | \(\dfrac{n-1}{n-3} \lambda \) | 2. | \(\dfrac{n}{n-3} \lambda \) |
| 3. | \(\dfrac{n-3}{n-1} \lambda \) | 4. | \(\dfrac{n+1}{n-3} \lambda\) |
Subtopic: Einstein's Photoelectric Equation |
73%
Level 2: 60%+
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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. \(2~\mathring{A}\)
1. \(0.25~\mathring{A}\)
2. \(0.5~\mathring{A}\)
3. \(1.5~\mathring{A}\)
4. \(2~\mathring{A}\)
Subtopic: De-broglie Wavelength |
79%
Level 2: 60%+
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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 |
60%
Level 2: 60%+
NEET - 2020
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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. \(3\times 10^{19}\)
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 |
74%
Level 2: 60%+
AIPMT - 2012
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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 |
69%
Level 2: 60%+
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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 |
82%
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 |
74%
Level 2: 60%+
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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 |
72%
Level 2: 60%+
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