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The intensity of a light pulse travellin...

The intensity of a light pulse travelling along an optical fibre decreases exponentially with distance according to the relation `l = i_(0) e^(-0.0693x)` where x is in km and `l_(0)` is intensity of incident pulse. The intensity of pulse reduces to `(1)/(4)` after travelling a distance

A

1km

B

10 km

C

20 km

D

40 km

Text Solution

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The correct Answer is:
C
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