When monochromatic photons of wavelength \(4000\) Å are incident on the metal plate of work function \(2.1\) eV, what will be the stopping potential for the photocurrent?
1. | \(1\) V | 2. | \(2.1\) V |
3. | \(3.1\) V | 4. | Zero |
When a point source of monochromatic light is at a distance of 0.2 m from a photoelectric cell, the cut-off voltage and saturation current are 0.6 volts and 18 mA respectively. What will happen if the same source is placed 0.6 m away from the photoelectric cell?
1. | the stopping potential will be 0.2 volts. |
2. | the stopping potential will be 0.6 volts. |
3. | the saturation current will be 6 mA. |
4. | the saturation current will be 18 mA. |
The variation of the kinetic energy \((K)\) of photoelectrons as a function of the frequency \((f)\) of the incident radiation is best shown by:
1. | 2. | ||
3. | 4. |
The correct graph between the maximum energy of a photoelectron \(\left(K_{max}\right)\) and the inverse of the wavelength \(\left(\frac{1}{\lambda}\right)\) of the incident radiation is given by the curve:
1. | \(A\) | 2. | \(B\) |
3. | \(C\) | 4. | None of these |
If alpha, beta and gamma rays carry the same momentum, which has the longest wavelength?
1. | Alpha rays | 2. | Beta rays |
3. | Gamma rays | 4. | None, all have same wavelength |
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.
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 |
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