Figure shows a part of an electric circuit. The potentials at points $a, b$ and $c$ are $30 V, 12 V$ and $2 V$ respectively. The current through the $20 Ω$ resistor will be,

Question

Figure shows a part of an electric circuit. The potentials at points a, b and c are 30 V, 12 V and 2 V respectively. The current through the 20 Ω resistor will be,

MARKS Content Team · Accepted Answer

Correct answer: (B) 0.4 A. Let the potential be x V at the junction. By using V=IR we get, 30-x=10i_1x-12=20i_2x-2=30i_3 By using Kirchhoff's law, i_1=i_2+i_3 ⇒(30-x)/10+(12-x)/20+(2-x)/30=0⇒(90-3x+18-1.5x+2-x)/30=0 ⇒x=20 V The current through the 20 Ω resistor is i_2=(30-12)/20 A ⇒i_2=8/20A=0.4 A

Figure shows a part of an electric circuit. The potentials at points $a, b$ and $c$ are $30 V, 12 V$ and $2 V$ respectively. The current through the $20 Ω$ resistor will be,

Solution

Relevant Questions