When the switch S is closed in the circuit shown in figure, the current passing through it is

Question

When the switch S is closed in the circuit shown in figure, the current passing through it is (A) 7.5 A (B) 3.0 A (C) 4.5 A (D) 6.5 A

Tardigrade Admin · Accepted Answer

<img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/10df20a008ad88b85c967b4b3f69f92f-.png" /> Let V be the potential at the junction. The currents through various arms will be as shown in figure. Here, I1+I2=I3 or (20-V/2)+(5-V/4)=(V-0/2) or 40-2 V+5-V=2 V or V=9 V ∴ I3=(9 V /2 Ω)=4.5 A

Q. When the switch $S$ is closed in the circuit shown in figure, the current passing through it is

7.5 A

3.0 A

4.5 A

6.5 A

Let $V$ be the potential at the junction.
The currents through various arms will be as shown in figure.
Here, $I_{1} + I_{2} = I_{3}$
or $\frac{20 - V}{2} + \frac{5 - V}{4} = \frac{V - 0}{2}$
or $40 - 2 V + 5 - V = 2 V$ or $V = 9 V$
$∴ I_{3} = \frac{9 V}{2 Ω} = 4.5 A$

Q. When the switch S is closed in the circuit shown in figure, the current passing through it is