Q. No.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 |
| 1. | \(\mathrm{Na}\) only | 2. | \(\mathrm{Cs}\) only |
| 3. | both \(\mathrm{Na}\) and \(\mathrm{K}\) | 4. | \(\mathrm{K}\) only |
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. | four times | 2. | one-fourth |
| 3. | zero | 4. | doubled |
The work function of the photosensitive material is \(4.0~\text{eV}\). The longest wavelength of light that can cause photoelectric emission from the substance is (approximately):
1. \(3100~\text{nm}\)
2. \(966~\text{nm}\)
3. \(31~\text{nm}\)
4. \(310~\text{nm}\)
Radiation of energy \(E\) falls normally on a perfectly reflecting surface. The momentum transferred to the surface is:
(\(c\) = velocity of light)
| 1. | \(E \over c\) | 2. | \(2E \over c\) |
| 3. | \(2E \over c^2\) | 4. | \(E \over c^2\) |
| 1. | \(V_0 /2\) | 2. | \(V_0 \) |
| 3. | \(4V_0 \) | 4. | \(2V_0 \) |
A \(200~\text{W}\) sodium street lamp emits yellow light of wavelength \(0.6~\mu\text{m}.\) Assuming it to be \(25\%\) efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is:
1. \(1.5\times 10^{20}\)
2. \(6\times 10^{18}\)
3. \(62\times 10^{20}\)
4. \(3\times 10^{19}\)
(take \(h\) as Plank's constant and \(c\) as the velocity of light in free space)
| 1. | \({e}+2\phi \) | 2. | \(2{e}-\phi \) |
| 3. | \({e}-\phi \) | 4. | \({e}+\phi \) |
(take \(h=6.62\times10^{-34}~\text{J s}\) and \(c=3\times10^{8}~\text{ms}^{-1}\))
| 1. | \(4.4~\text{eV}\) | 2. | \(7.103\times10^{-15}~\text{J}\) |
| 3. | \(1.9~\text{eV}\) | 4. | \(4.60~\text{eV}\) |
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