The conductivity of copper conductor is better than that of aluminum conductor, so the resistance of copper conductor is smaller

The conductivity of copper conductor is better than that of aluminum conductor, so the resistance of copper conductor is smaller

The resistance is also related to the cross-sectional area and length
It should be resistivity

How to judge whether the transformer is copper core or aluminum core according to the DC resistance of the transformer?

Do not ask, according to the DC resistance can not determine whether copper or aluminum
Generally speaking, aluminum is much higher than copper, and the whole volume is also much larger

When the current passing through the resistance R is I, the heat generated in time t is Q. if the resistance is 2R and the current is I, the heat generated in time t is Q

Q2 ∵ r = q △ I & sup2; t ∵ 2R = 2q △ I & sup2; × t ∵ 2R × I & sup2; × t = 2q △ I & sup2; × t × I & sup2; × t
I & sup2; × T and I & sup2; × T are approximately separated
∴2R＝2Q÷I²×t

Why do you guess that the heat generated by electrifying (the content of Joule's law) is related to current, resistance and electrifying time

Guess? Beginners? Well, after a long time of power on, wires and electric lights will heat up, so it's related to the time of power on. (common sense of life) as for the current, it's common sense that electric lights pass through a large current, so they will glow after incandescence, so it's related to the current. (seriously, it's hard to guess) resistance is a comparison in life