Conductivity and Ohm’s law
Answers are for parents and teachers.
1
U = 36 V, I = 9 A. What is R (Ω)?
4
2
If R = 0.25 Ω, what is the conductivity γ (S)?
4
3
An aluminium wire: ρ = 2.8·10⁻⁸ Ω·m, l = 50 m, S = 1.4·10⁻⁶ m². What is R (Ω)?
1
4
If the wire’s diameter doubles at the same length, how does its resistance change?
It falls 4 times (S ∝ d²).
5
Why are electric wires made of copper or aluminium?
They have high conductivity (low resistivity) and cost less than silver.