Question

Consider the following electric circuit:

Calculate the values of the following:

1. The total resistance of the circuit.
2. The total current drawn from the source.
3. Potential difference across the parallel combination of 10 Ω and 15 Ω resistors.

Answer 1

i. R₁ = 10, R₂ = 15, R₃ = 60, R₄ = 40

⇒ ${\displaystyle \frac{1}{R_p}=\frac{1}{R_1}+\frac{1}{R_2}}$

= ${\displaystyle \frac{1}{10}=\frac{1}{15}}$

= 6 Ω

⇒ ${\displaystyle \frac{1}{R_p}=\frac{1}{R_3}+\frac{1}{R_4}}$

= ${\displaystyle \frac{1}{60}+\frac{1}{40}}$

= 24 Ω

⇒ R₅ = 6 + 24

= 30 Ω

∴ The total resistance of the circuit is 30 Ω.

ii. V = IR

15 = I × 30

I = 0.5A

iii. R = 6 Ω

V = IR

V = 6 × 0.5

V = 3 volts