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
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.
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 |
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 |
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. |
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. |