Question

The internal resistance of an ammeter is $0.2\Omega$. Its full scale deflection current is $10\,A$. The potential difference across the terminals when a current of $5\,A$ is flowing through it is
A. 1 V
B. 1.6 V
C. 1.2 V
D. 1.4 V

Answer 1

Let’s discuss what is meant by internal resistance, internal resistance flows opposite to the current offered by cells and barriers results in the generation of heat. Now we can discuss in detail, from the given data we are going to find out the potential difference in internal resistance.

Complete step by step answer:
Given that, the internal resistance of an ammeter and deflection current, when the current is flowing across the terminal, we have to find the potential difference. That is, Potential difference (V) is when current (I) is passing through in it.From ohm's law,
$V=IR$
Here $V$ is the potential difference, $I$ is current and $R$ is internal resistance.
From the question given that,
$I=5\,A$ and
Internal resistance, $R=0.2\Omega$
By applying the values of $I$ and $R$ in the relation $V=IR$, then we get
$V = 5 \times 0.2 \\\ V = 1\,V \\\$
Hence, the correct option is A.

Note: The energy transferred between the two points in a circuit is called potential difference. Sometimes potential difference is also referred to as electromotive force. Ohm's law states that, between the two points the current is directly proportional to the voltage across. It is used for measuring the current levels and voltage supplies between the two points. Its unit is ohm$\left( \Omega \right)$.