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street lamps of 10 cm diameter and 1.8xx...

street lamps of 10 cm diameter and `1.8xx10^(5)cdm^(2)` luminance are suspended at a height of 12 m the distance bewteen them being 40 m Find the illuminance under each lamp and mid-way between them.

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The correct Answer is:
`10.38 lux, 2.7 lux`
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