Real-World Examples of Electrical Power in Everyday Life

📚 Quick Study Guide

• 💡 Electrical Power: The rate at which electrical energy is transferred by an electric circuit. Measured in Watts (W).
• ⚡ Formula: Power ($P$) = Voltage ($V$) x Current ($I$), or $P = VI$.
• 🔥 Another Formula: Using Ohm's Law ($V = IR$), we can also say $P = I^2R$ or $P = \frac{V^2}{R}$.
• 🏠 Household Voltage (Typical): 120V in North America, 230V in Europe.
• 🔢 Energy Consumption: Often measured in kilowatt-hours (kWh). 1 kWh is the energy used by a 1 kW device running for 1 hour.
• 📜 Key Terms: Voltage (potential difference), Current (flow of charge), Resistance (opposition to current).

Practice Quiz

1. What is the power consumed by a device that draws 2A of current at 120V?
   1. A. 60W
   2. B. 240W
   3. C. 122W
   4. D. 0.017W
2. A light bulb is rated at 60W and operates at 120V. What is the current flowing through it?
   1. A. 0.5A
   2. B. 2A
   3. C. 7200A
   4. D. 0.2A
3. A heater with a resistance of 10 ohms is connected to a 120V power supply. What is the power dissipated by the heater?
   1. A. 12W
   2. B. 1440W
   3. C. 1200W
   4. D. 10W
4. Which of the following appliances typically consumes the MOST electrical power?
   1. A. LED Light Bulb
   2. B. Refrigerator
   3. C. Microwave Oven
   4. D. Smartphone Charger
5. What unit is used to measure electrical energy consumption by households?
   1. A. Watt (W)
   2. B. Ampere (A)
   3. C. Kilowatt-hour (kWh)
   4. D. Volt (V)
6. If a device consumes 3 kWh of energy in 2 hours, what is its power rating in Watts?
   1. A. 1.5W
   2. B. 6W
   3. C. 1500W
   4. D. 6000W
7. Which formula correctly relates Power (P), Current (I), and Resistance (R)?
   1. A. $P = VI$
   2. B. $P = \frac{V}{I}$
   3. C. $P = I^2R$
   4. D. $P = V^2R$