Radiation with wavelength \(\lambda\) is incident on a photocell, causing the fastest emitted electron to have a speed \(v.\) If the wavelength is changed to \(\dfrac{3\lambda}{4},\) what will be the speed of the fastest emitted electron?
1. \( >v\left(\dfrac{4}{3}\right)^{\frac{1}{2}} \)
2. \( <v\left(\dfrac{4}{3}\right)^{\frac{1}{2}} \)
3. \( =v\left(\dfrac{4}{3}\right)^{\frac{1}{2}} \)
4. \( =v\left(\dfrac{3}{4}\right)^{\frac{1}{2}}\)
An electron beam is accelerated by a potential difference \(V\) to hit a metallic target to produce \({X}\)-ray. It produces continuous as well as characteristic \({X}\)-rays. If \(\lambda_{\text{min}}\) is the smallest possible wavelength of \({X}\)-ray in the spectrum, the variation of \(\log \lambda_{\text{min}}\) with \(\log V\) is correctly represented in:
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The figure shows the stopping potential \(V_0\) (in volts), as a function of frequency \(\nu,\) for a sodium emitter. From the data plotted in the graph, what is the work function of sodium?
(Given: Planck’s constant, \(h=\) \(6.63\times 10^{-34}~\text{J-s}\) and the charge of an electron, \(e=1.6\times 10^{-19}~\text{C}\))
1. | \(1.95~\text{eV}\) | 2. | \(2.12~\text{eV}\) |
3. | \(1.82~\text{eV}\) | 4. | \(1.66~\text{eV}\) |
In a photoelectric effect experiment, the graph of stopping potential \(V\) versus reciprocal of wavelength obtained is shown in the figure. As the intensity of incident radiation is increased:
1. | slope of the straight line get more steep. |
2. | straight line shifts to the right. |
3. | graph does not change. |
4. | straight line shifts to the left. |
Assertion (A): | The photoelectric effect does not take place if the energy of the incident radiation is less than the work function of a metal. |
Reason (R): | Kinetic energy of the photoelectrons is zero if the energy of the incident radiation is equal to the work function of a metal. |
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | (A) is False but (R) is True. |
A. | The square of maximum velocity of photoelectrons varies linearly with frequency of incident light. |
B. | The value of saturation current increases on moving the source of light away from the metal surface. |
C. | The maximum kinetic energy of photo-electrons decreases on decreasing the power of LED (light emitting diode) source of light. |
D. | The immediate emission of photo-electrons out of metal surface can not be explained by particle nature of light/electromagnetic waves. |
E. | Existence of threshold wavelength can not be explained by wave nature of light/electromagnetic waves. |
Which of the following statements correctly describes the photoelectric effect?
1. | The maximum kinetic energy of emitted electrons depends on the intensity of light. |
2. | The stopping potential depends only on the work function of the metal. |
3. | The photoelectric effect can be explained using the wave nature of light. |
4. | The photoelectric effect is best explained by the particle nature of light. |
1. | \(138~\text{nm}\) | 2. | \(130~\text{nm}\) |
3. | \(112~\text{nm}\) | 4. | \(145~\text{nm}\) |
Given below are two statements :
Assertion A: | Number of photons increases with increase in frequency of light. |
Reason R: | Maximum kinetic energy of emitted electrons increases with the frequency of incident radiation. |
1. |
Both A and R are correct and R is not the correct explanation of A
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2. |
Both A and R are correct and R is the correct explanation of A
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3. |
A is correct but R is not correct
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4. |
A is not correct but R is correct.
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