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? (A) 5min (B) 2.5min (C) 2.5 texts (D) 500 texts

Tardigrade Admin · Accepted Answer

Given: The distance of the moon (. s .) = 384000 textkm = 384000 × 103 textm We known speed of light (. c .) = 3 × (10)8 textm/s Total time taken by the laser beam to make the round trip is t=(2 s/c)=(2 × 384000 × 1000/3 × 108)=2.5 s

Q. 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?

$5 min$

$2.5 min$

$2.5 s$

$500 s$

Given:
The distance of the moon $(s) = 384000 km$
$= 384000 \times 1 0^{3} m$
We known speed of light $(c) = 3 \times (10)^{8} m/s$
Total time taken by the laser beam to make the round trip is
$t = \frac{2 s}{c} = \frac{2 \times 384000 \times 1000}{3 \times 1 0 ^{8}} = 2.5 s$

Q. 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 3,84,000km distance from earth, how long does it take the light to make the round trip?

5min

2.5min

2.5s

500s