Question

In the circuit given below:

(a) What is the combined resistance?
(b) What is the p.d. across the combined resistance?
(c) What is the p.d. across the 3 Ω resistor?
(d) What is the current in the 3 Ω resistor?
(e) What is the current in the 6 Ω resistor?

Answer 1

(a) The resistors of 6 Ω and 3 Ω are connected in parallel. Therefore, their combined resistance can be calculated as:
1/R = 1/R₁ + 1/R₂
Here, R₁ = 6 Ω ,
R₂ = 3 Ω
1/R = (1/6) + (1/3 )
1/R = (1 + 2)/6
R = 6/3
R = 2 Ω
(b) Potential difference, V = IR

Given, I = 6 A and R = 2 Ω
Thus the potential difference across the combined resistance,
V = (6 × 2) V
V = 12 V
(c) It can be seen here that the potential difference across the 3 Ω resistor is 12 V.

(d) The current across the 3 Ω resistor is:
I = V/R
I = 12/3
I = 4 A
(e) The current across the 6 Ω resistor is:
I = V/R
I = 12/6
I = 2 A