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. 2
C. 4
D. 3

Answer

B

Explanation

(b) When wireis cut into two equal parts then power dissipated by each parts is `2 P_(1)`
So their parallel combination will dissipated power
`P_(2) = 2 P_(1) + 2 P_(1) = 4 P_(1)`
Which gives `(P_(2))/(P_(1))` = 4`