Electricity - Power and Heating Effects Solved Examples (Class 10 Physics)
Electricity power and heating numericals explore electrical power consumption, heat generation, and energy efficiency. These problems explain electricity b
TL;DR: Electricity power and heating numericals explore electrical power consumption, heat generation, and energy efficiency. These problems explain electric…
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
Electricity power and heating numericals explore electrical power consumption, heat generation, and energy efficiency. These problems explain electricity b
Electricity - Power and Heating Effects — Solved Numerical Examples (Step by Step)
Example 1: An electric bulb rated 100 W operates at 230 V. Calculate the current through it.
Solution: Power P = 100 W, Voltage V = 230 V. Using P = V × I: 100 = 230 × I. Therefore I = 100 / 230 = 0.435 A.
Example 2: An electric heater draws 10 A current at 230 V. Calculate the power and energy consumed in 2 hours.
Solution: Current I = 10 A, Voltage V = 230 V. Power = V × I = 230 × 10 = 2300 W. Energy = Power × Time = 2300 × 2 = 4600 Wh = 4.6 kWh.
Example 3: A resistance of 50 ohms carries 4 A current. Calculate the power dissipated and heat generated in 5 minutes.
Solution: Resistance R = 50 ohm, Current I = 4 A. Power = I² × R = 16 × 50 = 800 W. Time = 5 minutes = 300 s. Heat = Power × Time = 800 × 300 = 240,000 J.
Example 4: An electric oven operates at 2 kW for 30 minutes daily. Calculate monthly energy consumption (30 days) and cost at 5 rupees per kWh.
Solution: Power = 2 kW, Daily time = 30 minutes = 0.5 hours. Daily energy = 2 × 0.5 = 1 kWh. Monthly energy = 1 × 30 = 30 kWh. Cost = 30 × 5 = Rs. 150.
Example 5: A 5 A fuse is used in a circuit with 230 V supply. What is the maximum power that can be safely used?
Solution: Current (safe) = 5 A, Voltage = 230 V. Maximum power = V × I = 230 × 5 = 1150 W.
Example 6: Two resistors of 20 ohm and 30 ohm are connected in series across 100 V. Calculate the current and power dissipated in the 20 ohm resistor.
Solution: Total resistance = 20 + 30 = 50 ohm. Current = V / R = 100 / 50 = 2 A. Power in 20 ohm resistor = I² × R = 4 × 20 = 80 W.
Tips
- Power = Voltage × Current (P = VI). Also P = I²R = V²/R.
- Energy = Power × Time. Express time in hours for kWh calculation.
- Electricity bills are based on kWh (kilowatt-hours), not watts.
Frequently Asked Questions
Why does my electricity bill increase in summer?
More electrical appliances (fans, air conditioners, refrigerators) run longer in summer, consuming more energy (kWh), which directly increases the bill.
What does a 5 A fuse mean?
A 5 A fuse breaks (interrupts) the circuit if current exceeds 5 A, protecting appliances from damage due to overload or short circuits.
More Physics Solved Examples
🤖 Stuck on any of these? Ask Syllab's free AI Tutor to explain step by step →