You have two wires made of two different metals(metal A and metal B). Both wires are the same thickness and length. You use both wires in two identical but seperate circuits. Metal A wire gets hot, while metal b dosnt. Why?

 ΔR = 5 s

Explanation:

The absolute uncertainty or error in an expression is

       ΔR = | | ΔB + | | ΔA

the absolute value guarantees to take the unfavorable case, that is, the maximum error.

We look for the derivatives

        = 1

        = -1

we substitute

       ΔR = 1 ΔB + 1 ΔA

of the data

       ΔB = 3 s

       ΔA = 2 s

       ΔR = 3 + 2

       ΔR = 5 s