Question

To verify Ohm's law, a student connects the voltmeter across the battery as, shown in the figure. The measured voltage is plotted as a function of the current, and the following graph is obtained:
If $V_0$ is almost zero, identify the correct statement:

• A. The value of the resistance $R$ is $1.5\Omega$
• B. The emf of the battery is $1.5V$ and the value of $R$ is $1.5\Omega$
• C. The emf of the battery is $1.5V$ and its internal resistance is $1.5$ $\Omega$
• D. The potential difference across the battery is $1.5V$ when it sends a current of $1000mA$

Answer 1

Answer: (C)

$V=E-Ir$
when $V=V_0=0\Rightarrow 0=E-Ir$
$\therefore E=r$
when $I=0,V=E=1.5V$
$\therefore r=1.5\Omega$.