Question

Why is much less heat generated in long electric cables?

Answer 1

much heat is generated in long cable wires because

resistance directly proportional to length

so more resistance

and Heat is directly proportional to resistance according Joule's law of heating.

Hope it helps!

Answer 2

according to Joules law H=I^2RT

so H is directly proportional to R

and R is directly proportional to length

so more resistance due to increased length

so much less heat generated..