A light of wavelength \(\lambda \) is incident on the metal surface and the ejected fastest electron has speed \(v.\) If the wavelength is changed to \(\frac{3\lambda}{4},\) then the speed of the fastest emitted electron will be:

1. smaller than \(\sqrt{\frac{4}{3}}v\)
2. greater than \(\sqrt{\frac{4}{3}}\)\(v\)
3. \(2v\)
4. zero

 
Subtopic:  Einstein's Photoelectric Equation |
 69%
From NCERT
AIPMT - 1998
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The work function of a metal surface is φ = 1.5 eV. If a light of wavelength 5000 Å falls on it, then the maximum K.E. of the ejected electron will be:

1. 1.2 eV 2. 0.98 eV
3. 0.45 eV 4. 0 eV
Subtopic:  Einstein's Photoelectric Equation |
 80%
From NCERT
AIPMT - 1998
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The current conduction in a discharge tube is due to:
1.  electrons only
2.  +ve ions and –ve ions
3.  –ve ions and electrons
4.  +ve ions and electrons

Subtopic:  Photoelectric Effect: Experiment |
From NCERT
AIPMT - 1999
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If a light of amplitude A and wavelength λ is incident on a metallic surface, then the saturation current flow is proportional to (assume cut-off wavelength = λ0):

1. A2, if λ > λ0

2. A2, if λ < λ0

3. A, if λ > λ0

4. A, if λ < λ0

Subtopic:  Photoelectric Effect: Experiment |
 57%
From NCERT
AIPMT - 1999
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Light of wavelength \(3000 ~{\mathring{\mathrm{A}}}\) in Photoelectric effect gives electron of maximum kinetic energy \(0.5 ~\text{eV}\). If the wavelength changes to \(2000 ~{\mathring{\mathrm{A}}}\) then the maximum kinetic energy of emitted electrons will be:

1. less than \(0.5 ~\text{eV}\)
2. \(0.5 ~\text{eV}\)
3. greater than \(0.5 ~\text{eV}\)
4. the photoelectric effect does not occur

Subtopic:  Einstein's Photoelectric Equation |
 81%
From NCERT
AIPMT - 1999
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If the K.E. of an electron and a photon is the same, then the relation between their de-Broglie wavelength will be:

1. λph < λe

2. λph = λe

3. λph > λe

4. λph =2 λe

Subtopic:  De-broglie Wavelength |
 52%
From NCERT
AIPMT - 1999
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The total energy of an electron is \(3.555~\text{MeV}\). Its kinetic energy will be:
1.  \(3.545~\text{MeV}\)
2.  \(3.045~\text{MeV}\)
3.  \(3.5~\text{MeV}\)
4.  none of the above

Subtopic:  Electron Emission |
From NCERT
AIPMT - 1999
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What did Einstein prove by the photo-electric effect?

1. E = h\(\nu\)

2. KE=12mv2

3. E=mc2

4. E=-Rhc2n2

Subtopic:  Einstein's Photoelectric Equation |
 60%
From NCERT
AIPMT - 2000
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Which one among the following shows the particle nature of light?
1. Photoelectric effect
2. Interference
3. Refraction
4. Polarization

Subtopic:  Particle Nature of Light |
 88%
From NCERT
AIPMT - 2001
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A photo-cell is illuminated by a source of light, which is placed at a distance \(d\) from the cell. If the distance becomes \(\frac{d}{2}\), then the number of electrons emitted per second will be: 
1. same
2. four times
3. two times
4. one-fourth

Subtopic:  Photoelectric Effect: Experiment |
 70%
From NCERT
AIPMT - 2001
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