Q. No.A photon of energy \(3.4~\text{eV}\) is incident on a metal having a work function of \(2~\text{eV}.\) The maximum \(K.E\) of photo-electrons is equal to:
1.
\(1.4~\text{eV}\)
2.
\(1.7~\text{eV}\)
3.
\(5.4~\text{eV}\)
4.
\(6.8~\text{eV}\)
The spectrum of radiation \(1.0\times 10^{14}\) Hz is in the infrared region.
The energy of one photon of this in joules will be:
1. \(6.62\times 10^{-48}\)
2. \(6.62\times 10^{-20}\)
3. \(\frac{6.62}{3}\times 10^{-28}\)
4. \(3\times 6.62\times 10^{-28}\)
| 1. | moves with one-fourth of energy as that of the initial energy. |
| 2. | moves with one-fourth of momentum as that of the initial momentum. |
| 3. | will be half in number. |
| 4. | will be one-fourth in number. |
The stopping potential for photoelectrons:
| 1. | does not depend on the frequency of the incident light. |
| 2. | does not depend upon the nature of the cathode material. |
| 3. | depends on both the frequency of the incident light and the nature of the cathode material. |
| 4. | depends upon the intensity of the incident light. |
| 1. | The stopping potential will decrease. |
| 2. | The stopping potential will increase. |
| 3. | The kinetic energy of emitted electrons will decrease. |
| 4. | The value of the work function will decrease. |
The stopping potential \(V\) for photoelectric emission from a metal surface is plotted along the \(Y\text-\)axis and the frequency \(\nu\) of incident light along the \(X\text-\)axis. A straight line is obtained as shown in the figure. Planck's constant is given by:
| 1. | the slope of the line. |
| 2. | the product of slope on the line and charge on the electron. |
| 3. | the product of intercept along the \(Y\text-\)axis and mass of the electron. |
| 4. | the product of the slope and mass of the electron. |
In an experiment on the photoelectric effect, the frequency \(f\) of the incident light is plotted against the stopping potential \(V_0.\) The work function of the photoelectric surface is given by:
(\(e\) is an electronic charge)
| 1. | \(OB\times e\) in eV |
| 2. | \(OB\) in volt |
| 3. | \(OA\) in eV |
| 4. | The slope of the line \(AB\) |
The stopping potential as a function of the frequency of the incident radiation is plotted for two different photoelectric surfaces \(A\) and \(B\). The graphs demonstrate that \(A\)'s work function is:
| 1. | Greater than that of \(B\). | 2. | Smaller than that of \(B\). |
| 3. | Equal to that of \(B\). | 4. | No inference can be drawn about their work functions from the given graphs. |
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