A laser beam is sent to the moon and reflected back to earth by a mirror placed on the moon by an astronaut. If the moon is at 3 , 84 , 000 km distance from earth, how long does it take the light to make the round trip?

Question

A laser beam is sent to the moon and reflected back to earth by a mirror placed on the moon by an astronaut. If the moon is at 3 , 84 , 000 km distance from earth, how long does it take the light to make the round trip?, 5 min, 2.5 min, 2.5 s, 500 s

MARKS App · Accepted Answer

Given: The distance of the moon ( s ) = 384000 km = 384000 × 10 3 m We known speed of light ( c ) = 3 × 10 8 m/s Total time taken by the laser beam to make the round trip is t = 2 s c = 2 × 384000 × 1000 3 × 10 8 = 2.5 s

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