# The wavelength $$\lambda_e$$ of an electron and $$\lambda_p$$ of a photon of the same energy $$E$$ are related by: 1. $$\lambda_p \propto \lambda_e$$ 2. $$\lambda_p \propto \sqrt{\lambda_e}$$ 3. $$\lambda_p \propto \frac{1}{\sqrt{\lambda_e}}$$ 4. $$\lambda_p \propto \lambda_e^2$$

Subtopic:  De-broglie Wavelength |
60%
From NCERT
AIPMT - 2013
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A $$200~\text{W}$$ sodium street lamp emits yellow light of wavelength $$0.6~\mu\text{m}$$. Assuming it to be $$25\%$$ efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is:
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 |
70%
From NCERT
AIPMT - 2012
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An $$\alpha\text-$$particle moves in a circular path of radius $$0.83~\text{cm}$$ in the presence of a magnetic field of $$0.25~\text{Wb/m}^2$$. The de-Broglie wavelength associated with the particle will be:
1. $$1~\mathring{\text{A}}$$
2. $$0.1~\mathring{\text{A}}$$
3. $$10~\mathring{\text{A}}$$
4. $$0.01~\mathring{\text{A}}$$

Subtopic:  De-broglie Wavelength |
58%
From NCERT
AIPMT - 2012
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A radioactive nucleus of mass M emits a photon of frequency $\nu$ and the nucleus will recoil. The recoil energy will be:

1.  $\frac{{\mathrm{h}}^{2}{\mathrm{\nu }}^{2}}{2{\mathrm{Mc}}^{2}}$

2.  zero

3.  $\frac{\mathrm{h\nu }}{\mathrm{c}\sqrt{2\mathrm{M}}}$

4.  $\frac{\mathrm{c}\sqrt{2\mathrm{M}}}{\mathrm{h\nu }}$

Subtopic:  De-broglie Wavelength |
64%
From NCERT
AIPMT - 2011
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In the photoelectric emission process from a metal of work function 1.8 eV, the kinetic energy of most energetic electrons is 0.5 eV. The corresponding stopping potential is:

1.  1.3 V

2.  0.5 V

3.  2.3 V

4.  1.8 V

Subtopic:  Photoelectric Effect: Experiment |
74%
From NCERT
AIPMT - 2011
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Light of two different frequencies, whose photons have energies of $$1$$ eV and $$2.5$$ eV respectively, illuminates a metallic surface whose work function is $$0.5$$ eV successively. The ratio of maximum speeds of emitted electrons will be:
1. $$1:2$$
2. $$1:1$$
3. $$1:5$$
4. $$1:4$$
Subtopic:  Einstein's Photoelectric Equation |
75%
From NCERT
AIPMT - 2011
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Electrons used in an electron microscope are accelerated by a voltage of 25 kV. If the voltage is 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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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, (power of S2)/(power of S1) is equal to:

1. 1.00

2. 1.02

3. 1.04

4. 0.98

Subtopic:  Photoelectric Effect: Experiment |
75%
From NCERT
AIPMT - 2010
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The potential difference that must be applied to stop the fastest photoelectrons emitted by a nickel surface, having work function 5.01 eV, when ultraviolet light of 200 nm falls on it, must be:

1. 2.4 V

2. -1.2 V

3. -2.4 V

4. 1.2 V

Subtopic:  Einstein's Photoelectric Equation |
61%
From NCERT
AIPMT - 2010
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Monochromatic light of wavelength 667 nm is produced by a helium-neon laser. The power emitted is 9mW. The number of photons arriving per second on average at a target irradiated by this beam is:
1. 9 x 1017

2. 3 X 1016

3. 9 x 1015

4. 3 X 1019

Subtopic:  Photoelectric Effect: Experiment |
78%
From NCERT
AIPMT - 2009
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