A point source kept at a distance of 1000 m has a illumination I. To change the illumination to 16I, the new distance should become

A point source kept at a distance of 1000 m has a illumination I. To c

1.	A point source kept at a distance of 1000 m has a illumination I. To change the illumination to 16I, the new distance should become
Answer» 250 m 500m 750 m 800 m Solution :`(I_(2))/(I_(1)) = ((r_(1))/(r_(2)))^(2)` `(161_(1))/(I_(1))=(1000)^(2)/(r_(2)^(2)),r_(2)=(1000)/(4)=250 m`

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A point source kept at a distance of 1000 m has a illumination I. To change the illumination to 16I, the new distance should become

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