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Q. No.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
The maximum kinetic energy of the emitted photoelectrons in the photoelectric effect is independent of the:
| 1. | work function of material |
| 2. | intensity of incident radiation |
| 3. | frequency of incident radiation |
| 4. | wavelength of incident radiation |
The wavelength of light in the visible region is about \(550~\text{nm}\) (average wavelength) for yellow-green colour. Three materials with work functions are given as \(Al~(4.28~\text{eV}),\) \(Cu~(4.65~\text{eV})\) and \(Na~(2.75~\text{eV}).\) From which of these photosensitive materials can you build a photoelectric device that operates with visible light?
1. \(Al\)
2. \(Cu\)
3. \(Na\)
4. none of the above
1. \(2\) V
2. \(3.2\) V
3. \(4.2\) V
4. \(5.2\) V
(\(e\) is electronic charge, \(h\) is Planck's constant, \(c\) is the velocity of light in vacuum)
| 1. | \(\dfrac{\lambda{P}}{h c} f\) | 2. | \(\dfrac{2\lambda{P}}{h c} f\) |
| 3. | \(\dfrac{\lambda{P}}{h c} f e\) | 4. | \(\dfrac{2\lambda{P}}{h c} f e\) |
| 1. | \(V_0 /2\) | 2. | \(V_0 \) |
| 3. | \(4V_0 \) | 4. | \(2V_0 \) |
In a photoelectric experiment, blue light is capable of ejecting a photoelectron from a specific metal while green light is not able to eject a photoelectron. Ejection of photoelectrons is also possible using light of the colour:
| 1. | yellow | 2. | red |
| 3. | violet | 4. | orange |
| 1. | be tripled | 2. | be more than tripled |
| 3. | be less than tripled | 4. | become one-third |
| 1. | a straight line with a positive intercept on the \(x\)-axis (frequency) |
| 2. | a straight line with a positive intercept on the \(y\)-axis (kinetic energy) |
| 3. | a parabola |
| 4. | a hyperbola |
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Q. No.
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