Electricity is the flow of electric charge that powers devices and makes things work.
Important Parts of Electricity:
- Electric Current: The flow of electric charge, measured in Amps (A).
- Voltage: The force that pushes the electric charge, measured in Volts (V).
- Resistance: The opposition to the flow of current, measured in Ohms (Ω).
- Ohm's Law: V = I × R – Voltage = Current × Resistance.
- Power: The amount of energy used, calculated by P = V × I (measured in Watts).
Types of Current:
- DC (Direct Current): Flows in one direction (like from a battery).
- AC (Alternating Current): Reverses direction (like in home electricity).
Practice Questions PDF
Download a printable worksheet on Electricity with answers.
Questions on Electricity
Showing 1–30 of 1281.An electric heater with a power rating of 2 kW is operated for 3 hours daily for the entire month of April. If the cost of electricity is Rs 6 per unit, what is the total electricity bill for the month? (Assume April has 30 days) 2.Assertion (A): Tungsten metal is used for making the filament of incandescent electric lamps. Reason (R): Tungsten has a very high melting point and produces light at high temperatures without melting. 3.Explain why the main power supply line coming into a house typically uses a thicker gauge copper wire compared to the thinner wires used for individual appliance connections within the house. 4.Two electric bulbs, rated 100W, 220V and 60W, 220V respectively, are connected in series to a 220V supply. Which bulb will glow brighter and why? 5.A circuit consists of three resistors: R1, R2, and R3. R1 = 5 Ω is connected in series with the parallel combination of R2 = 10 Ω and R3 = 10 Ω. If this circuit is connected to a 12V battery, what is the power dissipated across R1? 6.Explain why household electrical appliances are always connected in parallel with the main supply and not in series. 7.Assertion (A): Nichrome alloy is extensively used in the heating elements of electrical appliances like toasters and electric irons. Reason (R): Nichrome has a very high resistivity and a high melting point, making it suitable for producing significant heat without melting. 8.An electric heater is rated at 2.2 kW and operates on a 220 V household supply. What is the minimum rating of the fuse that should be used in the circuit to protect the heater? 9.A metallic wire of resistance R is stretched uniformly so that its new length becomes twice its original length. Assuming that its volume remains constant during stretching, what will be its new resistance? 10.A household circuit consists of two resistors, R1 = 6 Ω and R2 = 3 Ω, connected in parallel. This parallel combination is then connected in series with a third resistor, R3 = 8 Ω. If the entire circuit is connected to a 20 V battery, what is the current flowing through resistor R2? 11.The resistance of a circuit component is constant. If the voltage across it is halved, the current through it will: 12.The resistance of a conductor is 5 Ohm. If a current of 2A flows through it, the potential difference across its ends is: 13.A conductor has 10²0 free electrons passing through a cross-section in 2 seconds. The current flowing is: 14.If the voltage across a resistor is 10V and the current flowing is 2A, the power dissipated by the resistor is: 15.Which of the following is not a property of electric field lines? 16.How many joules are there in 1 calorie? 17.The formula for electric energy consumed (E) is: 18.A 100W bulb and a 40W bulb are connected in parallel to a 220V supply. Which bulb will glow brighter? 19.A 100W bulb and a 40W bulb are connected in series to a 220V supply. Which bulb will glow brighter? 20.Which of these is the most suitable material for a heating element? 21.What happens to the resistance of a conductor if its area of cross-section is increased? 22.The reciprocal of resistance is called: 23.In a parallel circuit, if one bulb fuses, the other bulbs: 24.In a series circuit, if one bulb fuses, the other bulbs: 25.Which combination of resistors provides the lowest equivalent resistance? 26.An electric iron of 1000 W is used for 2 hours daily. If the cost of 1 unit of electricity is Rs. 5, what is the cost of using the iron for 30 days? 27.What is the equivalent resistance of three 6 Ohm resistors connected in parallel? 28.What is the total power consumed by two lamps rated 60W and 40W, respectively, when connected in parallel across a 220V supply? 29.The resistance of a wire is R. If it is stretched to twice its original length, its new resistance will be: 30.If the current through a resistor is doubled, the heat produced in a given time interval will: