- 1(current)
Q. No.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 |
| 1. | \(1.2\) eV | 2. | \(0.98\) eV |
| 3. | \(0.45\) eV | 4. | \(0\) eV |
| 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. |
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. \(E = \frac{-Rhc^2}{n^2}\)
The value of Planck's constant is:
| 1. | \(6.63\times 10^{-34}~\text{J/s}\) | 2. | \(6.63\times 10^{-34}~\text{kg-}\text{m}^2\text{/s}\) |
| 3. | \(6.63\times 10^{-34}~\text{kg-}\text{m}^2\) | 4. | \(6.63\times 10^{-34}~\text{J-s}^2\) |
According to Einstein's photoelectric equation, the graph between the kinetic energy of photoelectrons ejected and the frequency of incident radiation is:
| 1. |  |
2. |  |
| 3. |  |
4. |  |
The work functions for metals \(A,B,\) and \(C\) are respectively \(1.92\) eV, \(2.0\) eV, and \(5\) eV. According to Einstein's equation, the metals that will emit photoelectrons for a radiation of wavelength \(4100~\mathring{A}\) is/are:
1. None
2. \(A\) only
3. \(A\) and \(B\) only
4. All the three metals
1. \(2\times 10^7~\text{m/s}\)
2. \(2\times 10^6~\text{m/s}\)
3. \(8\times 10^5~\text{m/s}\)
4. \(8\times 10^6~\text{m/s}\)
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Q. No.
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