Question

compare the power used in 3 ohm resistor in each of the following circuit (first) a 7 volt battery in series with 2 ohm and 3 ohm resistor (second) A 4 volt battery in parallel with 13 ohm and 4 ohm resistors ​

Answer 1

Explanation:

Potential difference (V) = 6 V

Here 1 Ω and 2 Ω resistors are connected in series.

∴ equivalent resistance of the circuit (R) = 1 + 2 = 3 Ω

According to Ohm’s law

V = IR

Or I=V/R=6/3=2A

the current through the circuit (I)=2A

Now the power used in the 2 Ω resistor

we know that Power = I2R

= 2×2×2=8W

(ii) Potential difference, V = 4 V

12 Ω and 2 Ω resistors are connected in parallel. The voltage across each component of a parallel circuit remains the same. Hence, the voltage across 2 Ω resistor will be 4 V. Power consumed by 2 Ω resistor is given by

∴ the power used by 2 Ω resistor is 8