In a circuit with a voltmeter and an ammeter used to measure current and voltage across a resistor, where should the ammeter and voltmeter be placed?

In a circuit with a voltmeter and an ammeter used to measure current and voltage across a resistor, where should the ammeter and voltmeter be placed?

• A. The ammeter should be placed before the resistor and the voltmeter after the resistor in its path.
• B. The ammeter should be placed before the resistor and the voltmeter across the resistor
• C. The voltmeter should be placed after the resistor and the ammeter in parallel with the resistor
• D. Both meters should be placed in parallel with the resistor

Answer: (A)

Measuring current and voltage correctly requires meters to be placed in the proper places so they don’t disturb the circuit. An ammeter must be in series with the component whose current you want to measure, so all the current flowing through the resistor also flows through the ammeter. A voltmeter, on the other hand, must be connected in parallel with the component so it can measure the voltage drop across that component without drawing significant current from the circuit. If you place the voltmeter in series, it would force a high-resistance path and give an incorrect voltage reading; if the ammeter is placed in parallel, it could short out part of the circuit or bypass the resistor, leading to wrong current measurement. So the correct setup is to place the ammeter in series with the resistor and connect the voltmeter across the resistor to read its voltage drop.

Measuring current and voltage correctly requires meters to be placed in the proper places so they don’t disturb the circuit. An ammeter must be in series with the component whose current you want to measure, so all the current flowing through the resistor also flows through the ammeter. A voltmeter, on the other hand, must be connected in parallel with the component so it can measure the voltage drop across that component without drawing significant current from the circuit.

If you place the voltmeter in series, it would force a high-resistance path and give an incorrect voltage reading; if the ammeter is placed in parallel, it could short out part of the circuit or bypass the resistor, leading to wrong current measurement. So the correct setup is to place the ammeter in series with the resistor and connect the voltmeter across the resistor to read its voltage drop.