How long would it take for a sound impulse to travel through a copper rod at 25 kilometers long

The purpose of a lab is to do your "expirements" the importance of the topic is so you can now what the story is about and the last one is because no one is me with my question ( what is 3 over 4 x - 9 = 27 maybe you can )

The modern-day generator works on the principle of electromagnetic induction discovered by michael faraday in 1831-32. faraday discovered that the above flow of electric charges could be induced by moving an electrical conductor, such as a wire that contains electric charges, in a magnetic field.

Answeroutward from: source;