Question

Calculate the power used in the 2 Ω resistor in each of the following circuits: a 6 V battery in series with 1 Ω and 2 Ω resistors.

Answer 1

As the 6 V battery is connected in series, the potential difference will be different across the two given resistors. So we need the current to calculate the power.

Therefore, the net resistance, R of the circuit

= (1 + 2) Ώ = 3 Ώ

Current, `I=V/R=6/3=2A`
Power consumed by the 2-ohm resistor,
P = I² R
   = 2² x 2
   = 8 W