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 same supply. Power dissipation in this case is `P_(2)`. Then, `P_(1) : P_(2)` is

Options

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

Answer

D

Explanation

`P_(1)=(V^(2))/(R )`
When wire is cut into two equal pieces, the resistance of each piece = `R//2`.
When they are in parallel to the main supply, then power dissipated
`P_(2)=(V^(2))/((R//2))+(V^(2))/((R//2))=4((V^(2))/(R))=4P_(1)`