Atomic StructureHard
Question
When a monochromatic point source of light is at a distance of 0.2 m from a phototelectric cell, the cut-off voltage and the saturation current are respectively 0.6 V and 18.0 mA. If the same source is placed 0.6 m away from the photoelectric cell, then
Options
A.the stoping potential will be 0.2 V
B.the stoping potential will be 0.6 V
C.the saturation current will be 6.0 mA
D.the saturation current will be 2.0 mA
Solution
(b) Stopping potential depends on two factors - one the energy of incident light and the other the work function of the metal. By increasing the distance of source from the cell, neither of the two changes. Therefore, stopping potential remains the same.
(d) Saturation current is directely proportional to the intensity of light incident on cell and for a point source, intensity I ∝ 1/r2
When distance is increased from 0.2 m to 0.6 m (three times), the intensity and hence the saturation current will decrease 9 times, i.e., the saturation current will be reduced to 2.0 mA.
(d) Saturation current is directely proportional to the intensity of light incident on cell and for a point source, intensity I ∝ 1/r2
When distance is increased from 0.2 m to 0.6 m (three times), the intensity and hence the saturation current will decrease 9 times, i.e., the saturation current will be reduced to 2.0 mA.
Create a free account to view solution
View Solution FreeMore Atomic Structure Questions
The flux of α - particle 2o is 1 × 106. The flux of α - particle at angle 60o is...Consider an atom made up of a proton and a hypothetical particle that has double the mass of an electron but the same ch...The radius of the orbit of an electron in a Hydrogen-like atom is 4.5 a0, where a0 is the Bohr radius. Its orbital angul...Electric conduction in a semi-conductor takes place due to :-...The angular momentum of an electron in the 2nd excited state of a Helium ion (He+) is...