The number of photoelectrons emitted for light of a frequency v (higher than the threshold frequency v0) is proportional to

1. v-v0

2. threshold frequency v0

3. intensity of light

4. frequency of light (v)

Subtopic:  Photoelectric Effect: Experiment |
 77%
From NCERT
NEET - 2009
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The work function of a surface of a photosensitive material is 6.2 eV. The wavelength of the incident radiation for which the stopping potential is 5V lies in the 

(1) ultraviolet region                               

(2) visible region

(3) infrared region                                   

(4) X-ray region 

Subtopic:  Einstein's Photoelectric Equation |
 57%
From NCERT
NEET - 2008
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A particle of mass \(1\) mg has the same wavelength as an electron moving with a velocity of \(3\times 10^{6}~\text{m/s}\). What will be the velocity of the particle? (mass of electrons = \(9.1\times 10^{-31}\) kg)
1. \(2.7 \times 10^{-18} ~\text{ms}^{-1}\)
2. \(9 \times 10^{-2} ~\text{ms}^{-1}\)
3. \(3 \times 10^{-31}~\text{ms}^{-1}\)
4. \(2.7 \times 10^{-21} ~\text{ms}^{-1}\)
Subtopic:  De-broglie Wavelength |
 51%
From NCERT
NEET - 2008
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An electron mass m with an initial velocity v=v0i^ v0>0 is in an electric field E=-E0 i^E0=constant > 0. It's de Broglie wavelength at the time t is given by:

(1) λ01+eE0mtv0

(2) λ01+eE0tmv0

(3) λ0

(4)λ0t.

Subtopic:  De-broglie Wavelength |
 64%
From NCERT
NEET - 2018
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The ratio of momenta of an electron and an \(\alpha \text-\)particle which are accelerated from rest by a potential difference of \(100~\text{V}\) is:
1. \(1\)
2. \(\sqrt{\frac{2m_e}{m_{\alpha}}}\)
3. \(\sqrt{\frac{m_e}{m_{\alpha}}}\)
4. \(\sqrt{\frac{m_e}{2m_{\alpha}}}\)

Subtopic:  Various Atomic Models |
 60%
From NCERT
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The fact that electric charges are integral multiples of the fundamental electronic charge was proved experimentally by 
(1) Planck                   

(2) J.J. Thomson

(3) Einstein                 

(4) Millikan

Subtopic:  Various Atomic Models |
 57%
From NCERT
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 A narrow electron beam passes undeviated through an electric field E = 3×104 volt/m and an overlapping magnetic field B=2×10-3 Weber/m2. If electric field and magnetic field are mutually perpendicular. The speed of the electrons is 
1. \(60\) m/s                       
2. 10.3×107 m/s
3. 1.5×107 m/s             
4. 0.67×10-7 m/s

Subtopic:  Lorentz Force |
 89%
From NCERT
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The specific charge of an electron is 

(a) 1.6×10-19 coulomb

(b) 4.8×10-10 stat coulomb

(c) 1.76×1011 coulomb/kg

(d) 1.76×10-11  coulomb/kg

Subtopic:  Various Atomic Models |
 54%
From NCERT
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Cathode rays are similar to visible light rays in that

(1) They both can be deflected by electric and magnetic fields

(2) They both have a definite magnitude of wavelength

(3) They both can ionize a gas through which they pass

(4) They both can expose a photographic plate

Subtopic:  Photoelectric Effect: Experiment |
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A beam of electrons is moving with constant velocity in a region having electric and magnetic fields of strength 20 Vm-1 and 0.5 T at right angles to the direction of motion of the electrons. What is the velocity of the electrons

1. 20 ms-1                  2. 40 ms-1 
3. 8 ms-1                    4. 5.5 ms-1

Subtopic:  Lorentz Force |
 92%
From NCERT
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