Question

A wire when connected to 220V mains supply has power dissipation P1. Now the wire is cut into two equal pieces

Answer 1

Let us assume, initially Resistance of wire = R and Voltage drop acoss it=V=220 Volt

Then, P1 = V2/R

When Wire is cut down into two pieces then each wire would have resistance R/2.

Now equivalent resistance of wire connected in parallel = R/4

Then, P2= V2/(R/4)= 4V2/R = 4P1

Hence, P2:P1 = 4