Question

Assume that a radio station is about 200 km away from your location and the station operates at 972 kHz. How long does it take for an electromagnetic signal to travel from the station to you and how many wave crests does it send out per second ? 

(a) 666 ms and 9.72 x 10⁵ crests per second 

(b) 666 ms and 972 x 10⁵ crests per second 

(c) 555 ms and 97.2 x 10⁷ crests per second 

(d) 555 ms and 0.972 x 10⁵ crests per second

Answer 1

The correct option is (a) 666 ms and 9.72 x 10⁵ crests per second.

Explanation:

Time taken by wave to travel

Number of crests per second = Frequency 

Frequency = 972 kHz = 9 .72 x 10⁵ Hz

There are 9.72 x 10⁵ crests per second.