A battery-operated torch is adjusted to send an almost parallel beam of light.

Monjur Alahi

A battery-operated torch is adjusted to send an almost parallel beam of light. It produces an illuminance of 40 lux when the light falls on a wall 2 m away. The illuminance produced when it falls on a wall 4 m away is close to

(a) 40 lux

(b) 20 lux

(c) 10 lux

(d) 5 lux.


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Salim Ahmed Kawsar

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The correct answer is
(a) 40 lux

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