In darkness, the typical value of the resistance of photo-conductive cell lies in the order of _____.

In darkness, the typical value of the resistance of photo-conductive cell lies in the order of _____.

a. 10 ohm
b. 100 ohm
c. 1000 ohm
d. 10000 ohm

Correct Answer : b. 100 ohm

Explanation :

Photo-conductive cells can be categorized under the family of photo-detectors which shows variation in the resistance due to incidence of light or any other form of radiant energy. The resistance value decreases with an increase in the intensity of incident light & hence the typical value of resistance of photo-conductive cells is absolutely 100 ohm. Materials like cadmium sulphide and silicon are used for photo conductive cells to greater extent since their conductivity is a function of incident radiant energy. Resistances of photo-conductive cell are noted along with the corresponding light intensities & then the resistances are expressed in terms of ohm while the light intensities are expressed in terms of meter candles (lux).