Refraction Of Light Video Lessons

Concept

# Problem: On the Moon's surface, lunar astronauts placed a corner reflector, off which a laser beam is periodically reflected. The distance to the Moon is calculated from the round-trip time. The Earth's atmosphere slows down light. Assume the distance to the Moon is precisely 3.84 x 108 m, and Earth's atmosphere (which varies in density with altitude) is equivalent to a layer 20.0 km thick with a constant index of refraction n = 1.000293. What is the difference in travel time for light that travels only through space to the moon and back and light that travels through the atmosphere and space?

###### FREE Expert Solution

Difference in travel time:

Δt = [2(n - 1)d]/c

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###### Problem Details

On the Moon's surface, lunar astronauts placed a corner reflector, off which a laser beam is periodically reflected. The distance to the Moon is calculated from the round-trip time. The Earth's atmosphere slows down light. Assume the distance to the Moon is precisely 3.84 x 108 m, and Earth's atmosphere (which varies in density with altitude) is equivalent to a layer 20.0 km thick with a constant index of refraction n = 1.000293. What is the difference in travel time for light that travels only through space to the moon and back and light that travels through the atmosphere and space?