Q.

When a potential difference V is applied across a wire of resistance R, it dissipates energy at a rate W. If the wire is cut into two halves and these halves are connected mutually parallel across the same supply, the energy dissipation rate will become          [2024]

1 1/4 W  
2 1/2 W  
3 2W  
4 4W  

Ans.

(4)

W=V2R                          ...(1)

and R=ρA

Now 

Req=R4

W'=V2R4=4V2R=4W