Question

Determine the current at point A in this circuit.

A) 2.6 A
B) 1.6 A
C) 1.8 A
D) 2.4 A

Answer 1

2.6 A

Step-by-step explanation:

Firstly here we need to find out the net resistance. 30Ω and 40Ω are grouped in parallel and to these 10Ω and 15Ω are in series. So we can find the net resistance as ,

`\implies R_(net)=(R_1R_2)/(R_1+R_2) \\`

`\implies R_(net)=(30* 40)/(30+70)\Omega \\`

`\implies R_(net)=(120)/(7)\Omega \\`

Again,

`\implies R_(net)= R_1 + R_2+R_3 \\`

`\implies R_(net)=(120)/(7)+10+15\Omega \\`

`\implies R_(net)= (120+105+70)/(7)\Omega\\`

`\implies R_(net)= (295)/(7)\Omega \approx 42\Omega \\`

Now use Ohm's law as ,

`\implies V = iR \\`

`\implies 110V = i* 42\Omega\\`

`\implies i =(110)/(42) A\\`

`\implies \underline{\underline{ i = 2.6\ A }} \\`

and we are done!