InterviewSolution
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InterviewSolution
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When a monochromatic point source of light is at a distance of 0.2 m from a photoelectric 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 (a) the stopping potential will be 0.2 V (b) the stopping potential will be 0.6 V (c ) the saturation current will be 6.0 mA (d) the saturation current will be 2.0 mAA. The stopping potential will be `0.2 V`B. the stopping potential will be `0.6 V`C. the saturation current will be `6 mA`D. the saturation current will be `18 mA` |
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Answer» Correct Answer - C Cut off `"voltage"` is independent of intensity and hence remains the same. Since distance becomes `3 times`, so intensity `(I)` becomes `(I)/(9)`. Hence photo current also decreases by this factor i.e., becomes `(18)/(9) = 2 mA`. |
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