Question

When a voltmeter and an ammeter are connected one by one across the terminals of a cell respectively measures $5\text{V}$ and $10\text{A}$. Now all meters are removed and only a resistance of $2\Omega$ is connected across the terminals of the cell. The current flowing through this resistance is:

• A. $7.5\text{A}$
• B. $5.0\text{A}$
• C. $2.5\text{A}$
• D. $2.0\text{A}$

Answer 1

The correct option is D $2.0\text{A}$


Reading of voltmeter $=5\text{V}$,
Ideally, $R_{voltmeter}=\infty$

So, $E=5\text{V}........\left(1\right)$


Reading of ammeter, $i=10\text{A}$
Ideally $R_{ammeter}=0$

So, $5-ir=0\Rightarrow 5=10r$

$\therefore r=\frac{1}{2}\Omega$

Now,

$R_{eq}=2.5\Omega$

So the current flowing through the circuit will be

$i=\frac{5}{2.5}=2\text{A}$

Hence, option $\left(\text{D}\right)$ is correct.