A wire when connected to 220 V mains supply has power dissipation `P_1`. Now the wire is cut into two equal pieces which are connected in parallel to the same supply. Power dissipation in this case is `P_2`. Then `P_2: P_1` is

Options

A. 1
B. 4
C. 2
D. 3

Answer

B

Explanation

(b) Case 1 : `P_1 = V^2/R`

Case 2 : The wire is cut into two equal pieces. Therefore the resistance of the individual wire is R/2. These are connected in parallel
`:. R_(eq) = (R//2)/2 = R/4` ,