Question

Electromagnetic radiations travel with a speed of 3x 10^8 m/sec. If the radio signal takes 1.3 sec to
reach the earth then distance of the moon from the earth is
(a) 2 x 10^3 km (b) 3.5x 10^3 cm
(c) 3.9 x 10^3 km (d) 3.9 x 10^8 km

plz tell the right answer with explanation ​

Answer 1

Answer:

Solution: This is simple unit conversion. From the book (and I would give you this information on a quiz or test), 1 pc (parsec) = 3.09 x 1013 km. So the distance to Procyon is

3.50 pc x 3.09 x 1013 km/pc = 10.8 x 1013 km = 1.08 x 1014 km. (note, I only care about 10% accuracy in answers, so 1.1 x 1014 or even 1 x 1014 km would be acceptable).

(b) How long (in