Chapter 29, Problem 50A

A radio wave sent into space strikes an asteroid and is reflected back to Earth 1 second after being emitted. How far away is the asteroid?

To determine

To find: the distance of asteroid from the earth when a radio wave strikes an asteroid and reflected the earth $1$ second after being emitted.

Explanation of Solution

Introduction: 

Radio waves have the longest wavelength in the electromagnetic spectrum, the waves which receive the electromagnetic radiation and converts into the mechanical vibrations.

Explanation: 

A radio wave is sent to the asteroid from the earth and it reaches in a certain time (in seconds) and that radio wave reflected the earth $1$ second after which means, the radio wave travelled in $0.5$ seconds to reach the asteroid. 

The speed of the reflected radio wave is the same as that of the incident wave ad so the time. Therefore, the distance from the earth to the asteroid is $1.5\times {10}^8$ meters. It is obtained by multiplying the time $0.5$ seconds and speed of light. 

Conclusion: 

The radio wave has taken the time to reach the asteroid is $0.5$ seconds from the earth. So, the distance between the earth and the asteroid is $1.5\times {10}^8$ m.