In the photoelectric emission process from a metal of work function 1.8 eV, the kinetic energy of most energetic electrons is 0.5 eV. What is the corresponding stopping potential?
1. 1.3 V
2. 0.5 V
3. 2.3 V
4. 1.8 V
1. | decrease by 2 times |
2. | decrease by 4 times |
3. | increase by 4 times |
4. | increase by 2 times |
A source S1 is producing, 1015 photons per sec of wavelength 5000 Å. Another source S2 is producing 1.02×1015 photons per second of wavelength 5100 Å. Then the ratio of the power of S2 to the power of S1 is equal to:
1. | 1.00 | 2. | 1.02 |
3. | 1.04 | 4. | 0.98 |
Monochromatic light of frequency 6.0×1014 Hz is produced by a laser. The power emitted is 2×10-3 W. What will be the average number of photons emitted by the source per second?
1.
2.
3.
4.
When photons of energy h fall on an aluminium plate (of work function E0), photoelectrons of maximum kinetic energy K are ejected. If the frequency of the radiation is doubled, the maximum kinetic energy of the ejected photoelectrons will be:
1.
2. 2K
3. K
4. K+h
In an experiment of the photoelectric effect, the wavelength of incident radiation is . The wavelength of incident radiation is reduced to rd of initial value and the maximum kinetic energy of photoelectron is observed to be n times the previous value.
What will be the threshold wavelength for the metal plate?
1. \(\frac{n-1}{n-3} \lambda \)
2. \(\frac{n}{n-3} \lambda \)
3. \(\frac{n-3}{n-1} \lambda \)
4. \(\frac{n+1}{n-3} \lambda\)
The de-Broglie wavelength of a particle accelerated by a 150 volt potential difference is 10-10 m. What will its wavelength be if it is accelerated by a 600 volt potential difference?
1. 0.25
2. 0.5
3. 1.5
4. 2
Light of a frequency of \(1.5\) times the threshold frequency is incident on a photosensitive material. What happens to the photoelectric current when the frequency is cut in half and the intensity is doubled?
1. | four times | 2. | one-fourth |
3. | zero | 4. | doubled |
An electron is accelerated from rest through a potential difference of \(V\) volt. If the de Broglie wavelength of an electron is \(1.227\times10^{-2}~\text{nm}\). what will be its potential difference?
1. \(10^{2}~\text{V}\)
2. \(10^{3}~\text{V}\)
3. \(10^{4}~\text{V}\)
4. \(10^{5}~\text{V}\)
A 200 W sodium street lamp emits yellow light of wavelength 0.6 . If it is 25% efficient in converting electrical energy to light, how many photons of yellow light does it emit per second?
1.
2.
3.
4.