Question

Three resistors 20Ω, 30Ω and 40Ω are in parallel. Determine (i) Total resistance of the circuit, (ii) Current through each resistance, (iii) Total current and (iv) Total power dissipated in the circuit. Assume the voltage applied to this circuit is 20V.​

Answer 1

Explanation:

(i)1/Rp=1/R1+1/R2+1/R3

1/Rp=1/20+1/30+1/40

1/Rp=6+4+3/120

Rp=120/13=9.23 ohm

(ii) In parallel circuits,voltages are same

I1=V/R1=20/20= 1 A

I2=V/R2=20/30=0.67 A

I3=V/R3=20/40=0.5 A

(iii)I=I1+I2+I3

I=1+0.67+0.5

I=2.17 A

(iv)P=V^2 / Rp=400/9.23=43.34 W