Question

In making an Ohm’s law circuit., which of the following connections is correct?
A. voltmeter in series and ammeter in parallel
B. voltmeter in parallel and ammeter in series
C. voltmeter and ammeter both are in parallel
D. voltmeter and ammeter both are in series

Answer 1

Hint: A voltmeter is an instrument, which is used to measure the potential difference across a component of the circuit. An ammeter is an instrument which is used to measure the amount of current flowing in the circuit or through any component.

Complete answer:
A voltmeter is an instrument, which is used to measure the potential difference across a component of the circuit. It consists of two terminals – one positive and the other negative. These two terminals are connected to the two ends of the circuit component (may be a resistance, a capacitor or an inductor).

Since we have to find the potential difference across the two ends of the component, the voltmeter must always be connected in parallel to the components.An ammeter is an instrument which is used to measure the amount of current flowing in the circuit or through any component. It also consists of two terminals. The current is measured at a point.

Therefore, the ammeter must be connected in series with the circuit components.Ohm’s law states that voltage (potential difference) across a resistance in a circuit is directly proportional to the current flowing through it.Therefore, in Ohm’s law voltmeter is connected in parallel to the resistor and ammeter is connected in series.

Hence, the correct option is B.

Note: A voltmeter measures the potential difference across a component and it cannot measure the emf of a cell. This is because emf of a cell is not equal to the potential difference across it when it is connected in a circuit.