Electrons used in an electron microscope are accelerated by a voltage of 25 kV. If the accelerating voltage is reduced to 6.25 kV, the resolving power of the microscope would:

1. Increase to 4 time

2. Increases to 2 times

3. Decrease to half

4. Decrease to 1/4th

Subtopic:  De-broglie Wavelength |
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When the light of wavelength λ is used in a photoelectric experiment, the maximum kinetic energy of emitted electrons is found to be K. What will the maximum kinetic energy of the photoelectrons when the light of wavelength λ2 is used instead of λ:

1. Zero

2. Non zero but less than 2 K

3. 2K

4. More than 2K

Subtopic:  Einstein's Photoelectric Equation |
 54%
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If the momentum of a photon is p, then its energy is :

1.  pc

2.  12pc  

3.  p22c  

4.  14pc

 

Subtopic:  De-broglie Wavelength |
 60%
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For non-relativistic speeds, the wavelength associated with an electron and its kinetic energy E are related as:

1.  λ  E 

2.  λ  E-1  

3.  λ  E1/2 

4.  λ  E-1/2

 

Subtopic:  Davisson & Germer Experiment (OLD NCERT) |
 56%
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An electron at rest is acceleration by a potential difference of 600V. The de-Broglie wavelength associated with the electron is:

1.  1Ao

2.  2Ao

3.  3Ao

4.  0.5 Ao

 

Subtopic:  Davisson & Germer Experiment (OLD NCERT) |
 74%
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The de-Broglie wavelength of a body of mass 1 kg moving with a velocity of 2000 m/s is

1.  3.32 x 10-27 Ao  

2.  1.5 x 107 Ao  

3.  0.55 x 10-22 Ao 

4.  None of these

Subtopic:  De-broglie Wavelength |
 74%
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Light of wavelength 4000 Å falls on a photosensitive metal and a negative 2V potential stops the emitted electrons.

The work function of the material (in eV) is approximately 

h=6.6 x 10-34 Js, e=1.6 x 10-19 C, c=3 x 108 ms-1
1.  1.1

2.  2.0

3.  2.2

4.  3.1

Subtopic:  Photoelectric Effect: Experiment |
 75%
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The work functions for metal A, metal B, and metal C are ϕA,ϕB and ϕC respectively. Then-

                                 

1.   ϕA < ϕB < ϕC  

2.  ϕA = ϕB < ϕC  

3.  ϕA > ϕB > ϕC

4.  None of these

Subtopic:  Einstein's Photoelectric Equation |
 71%
From NCERT
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A particle of mass M at rest decays into two masses  \(m_{1}\) and \(m_{1}\)  having non-zero velocities. What will be the ratio of their de-Broglie wavelengths?

1. \(\frac{m_1}{m_2} \) 2. \(\frac{m_2}{m_1} \)
3. \(1 \) 4. \(\sqrt{\frac{\mathrm{m}_2}{\mathrm{~m}_1}}\)
Subtopic:  De-broglie Wavelength |
From NCERT
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The ratio of wavelengths of the last line of Balmer series and the last line of Lyman series is: 

(1) 2

(2) 1

(3) 4

(4) 0.05

Subtopic:  Spectral Series |
 73%
From NCERT
NEET - 2017
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