Question

In the circuit given below:    

 

(a) What is the combined resistance?
(b) What is the p.d. across the combined resistor?
(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
The potential difference across the combined resistance,
V = `(6xx2)` V
V = 12 V

(c) The potential difference across the 3 Ω resistor can be calculated as:
 V = IR
 V =`6xx3`= 18 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