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 \(\phi = 1.5\) eV. If a light of wavelength \(5000~\mathring{A}\) 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 |
 58%
From NCERT
AIPMT - 1999
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Light of wavelength \(3000 ~{\mathring{A}}\) in Photoelectric effect gives electron of maximum kinetic energy \(0.5 ~\text{eV}\). If the wavelength changes to \(2000 ~{\mathring{A}}\) 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 |
 82%
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. \(\lambda_{ph}< \lambda_e\)
2. \(\lambda_{ph}= \lambda_e\)
3. \(\lambda_{ph}>\lambda_e\)
4. \(\lambda_{ph}= 2\lambda_e\)
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. \(K.E = \frac{1}{2}mv^2\)
3. \(E= mc^2\)
4. \(E = \frac{-Rhc^2}{n^2}\)

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. Polarisation
Subtopic:  Particle Nature of Light |
 90%
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 \(\dfrac{d}{2}\), 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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