Question

In the circuit shown below emf of each batter y is 5V; and has an internal resistance of $1.0\Omega$.The current in the circuit $\left(I_0\right)$ and the reading in an ideal voltmeter (V) are

• A. $I_0=1A,V=0$
• B. $I_0=5A,V=0$
• C. $I_0=1A,V=1$
• D. $I_0=5A,V=1$

Answer 1

The correct option is B $I_0=5A,V=0$

Equivalent emf of the circuit $E_{eq}=E+E+E+E+E+E+E+E=8E$
$\therefore$ $E_{eq}=8\times 5=40V$
Equivalent resistance of circuit $r_{eq}=8r=8\times 1=8\Omega$
Current through the circuit $I_o=\frac{E_{eq}}{r_{eq}}=\frac{40}{8}=5V$
Voltmeter reading $V=E-Ir=5-5\times 1=0$