The same mass of copper is drawn into two wires 1mm and 2mm thick respectively. If the two wires are connected in series and current is passed through them, what is ratio of heat produced in the wires?

16:1

same mass ⇒ same volume

\(\frac{A1}{A2}\) = (\(\frac{r1}{r2}\))²

L1 A1 = L2 A2 ⇒ \(\frac{A1}{A2}\) = \(\frac{L2}{L1}\) = 1 : 4 

Resistances : \(\frac{R1}{R2}\) = \(\frac{L1}{A1}\) : \(\frac{L2}{A2}\) = 16 : 1