A radio signal with a wavelength of 1.2 x 10–4 m is sent to a distance asteroid, is reflected, and returns to Earth 72 hours and 48 minutes later. How far from Earth is the asteroid?
A) 1.9 x 1010 km
B) 3.9 x 1010 km
C) 7.9 x 1010 km
D) 1.9 x 1011 km
E) 5.4 x 1011 km
The correct option is: (B) 3.9 x 1010 km
Explanation:
It travels at light speed and takes half the total time to travel the distance one way. Use v=d/t. Convert the time to seconds, find the distance in meters, then convert that to km.
