Question

Calculate the power used in the 2 Ω resistor in each of the following circuits: a 4 V battery in parallel with 12 Ω and 2 Ω resistors. 

Answer 1

 As the battery is connected in parallel to the 12 Ώ and 2 Ώ resistors, the potential difference across them will be the same.
Therefore, the power 

`P=V^2/R` 

`P=4^2/2=16/2= 8 W`