# A certain metallic surface is illuminated with monochromatic light of wavelength λ. The stopping potential for photoelectric current for this light is 3Vo. If the same surface is illuminated with light of wavelength 2λ, the stopping potential is Vo. <!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> The photoelectric effect's threshold wavelength for this surface is? 1. 6λ 2. 4λ 3. λ/4 4. λ/6

Subtopic:  Einstein's Photoelectric Equation |
77%
From NCERT
NEET - 2015
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Which of the following figures represents the variation of the particle momentum and the associated de-Broglie wavelength?

 1 2 3 4
Subtopic:  De-broglie Wavelength |
85%
From NCERT
NEET - 2015
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A photoelectric surface is illuminated successively by monochromatic light of wavelengths λ and λ/2. If the maximum kinetic energy of the emitted photoelectrons in the second case is 3 times that in the first case, the work function of the surface of the material will be:
(h = Planck’s constant, c = speed of light)

1. hc/2λ

2. hc/λ

3. 2hc/λ

4. hc/3λ

Subtopic:  Einstein's Photoelectric Equation |
71%
From NCERT
NEET - 2015
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Light with a wavelength of 500 nm is incident on a metal with a work function of 2.28 eV. The de Broglie wavelength of the emitted electron will be:
1. $$<2.8 \times 10^{-10} \mathrm{~m}$$
2. $$<2.8 \times 10^{-9} \mathrm{~m}$$
3. $$\geq 2.8 \times 10^{-9} \mathrm{~m}$$
4. $$<2.8 \times 10^{-12} \mathrm{~m}$$

Subtopic:  De-broglie Wavelength |
60%
From NCERT
NEET - 2015
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Light with an energy flux of $$25\times 10^{4}~\text{Wm}^{-2}$$ falls on a perfectly reflecting surface at normal incidence. If the surface area is $$15~\text{m}^2$$, then the average force exerted on the surface is:
1. $$1.25\times 10^{-6}~\text{N}$$
2. $$2.5\times 10^{-6}~\text{N}$$
3. $$1.2\times 10^{-6}~\text{N}$$
4. $$3.0\times 10^{-6}~\text{N}$$

Subtopic:  Particle Nature of Light |
62%
NEET - 2014
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When the energy of the incident radiation is increased by 20%, the kinetic energy of the photoelectrons emitted from a metal surface increases from 0.5 eV to 0.8 eV. The work function of the metal will be:
1. 0.65 eV

2. 1.0 eV

3. 1.3 eV

4. 1.5 eV

Subtopic:  Einstein's Photoelectric Equation |
67%
From NCERT
NEET - 2014
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What will be the percentage change in the de-Broglie wavelength of the particle if the kinetic energy of the particle is increased to 16 times its previous value?
1. 25
2. 75
3. 60
4. 50

Subtopic:  De-broglie Wavelength |
69%
From NCERT
NEET - 2014
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The wavelength $$\lambda_{e}$$ of an electron and $$\lambda_{p}$$ of a photon of the same energy E are related as:

1. ${\lambda }_{p}\propto {{\lambda }_{e}}^{2}$

2. ${\lambda }_{p}\propto {\lambda }_{e}$

3. ${\lambda }_{p}\propto \sqrt{{\lambda }_{e}}$

4. ${\lambda }_{p}\propto \frac{1}{\sqrt{{\lambda }_{e}}}$

Subtopic:  De-broglie Wavelength |
54%
From NCERT
NEET - 2013
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A 200W sodium street lamp emits yellow light of wavelength  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) $1.5×{10}^{20}$

(2) $6×{10}^{18}$

(3) $62×{10}^{20}$

(4) $3×{10}^{19}$

Subtopic:  Electron Emission |
68%
From NCERT
NEET - 2012
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Monochromatic radiation emitted when electron on hydrogen atom jumps from first excited to the ground state irradiates a photosensitive material. The stopping potential is measured to be 3.57 V.The threshold frequency of the material is:

(1)$4×{10}^{15}Hz$

(2)$5×{10}^{15}Hz$

(3)$1.6×{10}^{15}Hz$

(4)$2.5×{10}^{15}Hz$

Subtopic:  Einstein's Photoelectric Equation |
64%
From NCERT
NEET - 2012
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