Voltmeter Uses: Practical Examples Explained

📚 Quick Study Guide

• ⚡ A voltmeter measures the potential difference (voltage) between two points in a circuit.
• 📏 Voltmeters are always connected in parallel with the component across which the voltage is to be measured.
• 💡 Ideal voltmeters have infinite resistance to avoid drawing current from the circuit.
• 📝 The SI unit of potential difference is the volt (V).
• ➗ Voltage can be calculated using Ohm's Law: $V = IR$, where $V$ is voltage, $I$ is current, and $R$ is resistance.
• 🌡️ Analog voltmeters use a needle to indicate the voltage on a scale, while digital voltmeters display the voltage numerically.
• ⚙️ Voltmeters are essential tools for diagnosing electrical problems in various applications.

🧪 Practice Quiz

1. Which of the following describes the primary function of a voltmeter?
   1. Measuring current
   2. Measuring resistance
   3. Measuring voltage
   4. Measuring power
2. How should a voltmeter be connected in a circuit to measure the voltage across a resistor?
   1. In series with the resistor
   2. In parallel with the resistor
   3. Without any connection to the resistor
   4. Connected to the power source only
3. What is the ideal internal resistance of a voltmeter?
   1. Zero
   2. Low
   3. High
   4. Infinite
4. According to Ohm's Law, how is voltage (V) related to current (I) and resistance (R)?
   1. $V = I/R$
   2. $V = IR$
   3. $V = I + R$
   4. $V = R/I$
5. In a household circuit, a voltmeter reads 120V. What does this indicate?
   1. The current flowing through the circuit
   2. The resistance of the circuit
   3. The potential difference across the circuit
   4. The power consumed by the circuit
6. Which type of voltmeter displays the voltage as a numerical value?
   1. Analog voltmeter
   2. Digital voltmeter
   3. Electrolyte voltmeter
   4. Ammeter
7. A voltmeter is used to check a car battery and reads 12.6V. What does this reading generally indicate?
   1. The battery is completely discharged
   2. The battery is fully charged or near full charge
   3. The battery is faulty and needs replacement
   4. The battery is being charged too quickly