He earliest radio broadcasts on Earth were emitted about 100 years ago. Approximately where are these initial radio waves now? (Radio waves are a type of radiation, so they travel at the speed of light)

Explanation:

Radio waves are electromagnetic waves.

Electromagnetic waves travel in a vacuum at the speed of light, which is:

Therefore, the distance they cover in a time t is

where d is the distance covered.

In this problem, the time elapsed is

t = 100 y

Keeping in mind that

So the time elapsed in seconds is

And therefore, the distance covered by the radio waves in this time is

coil wire, increase current, put iron inside the coil