Class 10 Physics: Chapter 11 Electricity
Multiple Choice Questions (20 MCQs)
1. What is the unit of electric current?
Answer: b) Ampere
2. A voltmeter is connected:
Answer: b) In parallel
3. Ohm’s law establishes relation between:
Answer: c) Voltage and Current
4. Resistance of a wire depends on:
Answer: d) All of these
5. In series circuit, current:
Answer: b) Is same through all components
6. The SI unit of resistance is:
Answer: a) Ohm
7. The heating effect of current is used in:
Answer: d) All of these
8. Which law relates voltage and current?
Answer: c) Ohm’s law
9. In a parallel circuit, the voltage across each resistor is:
Answer: b) Same
10. Electric power is measured in:
Answer: a) Watt
Short Answer Questions (20 questions)
1. Define electric current.
Electric current is the rate of flow of electric charges through a conductor.
2. What is potential difference?
Potential difference is the work done in moving a unit charge from one point to another.
3. State Ohm’s law.
The current through a conductor is directly proportional to the voltage across it, provided temperature is constant.
4. What is resistance?
Resistance is the property of a material that opposes the flow of electric current.
5. How are resistors combined in series?
Their total resistance is the sum of individual resistances.
6. How are resistors combined in parallel?
The reciprocal of total resistance is the sum of reciprocals of individual resistances.
7. What device is used to measure electric current?
Ammeter.
8. What device is used to measure potential difference?
Voltmeter.
9. Define resistivity.
Resistivity is a property of a material that indicates how much it resists current.
10. State the unit of electric power.
Watt (W).
11. What is Joule’s law of heating?
The heat produced in a resistor is proportional to the square of current, resistance, and time.
12. How does the length of wire affect its resistance?
Resistance is directly proportional to the length of the wire.
13. How does the thickness of wire affect resistance?
Resistance is inversely proportional to the cross-sectional area of the wire.
14. What is a series circuit?
A circuit where components are connected end-to-end so that current is the same through all.
15. What is a parallel circuit?
A circuit where components are connected in parallel branches and voltage is the same across each.
16. How is electric power calculated?
Power equals voltage multiplied by current
P = VI.17. What is the role of a fuse in an electric circuit?
It protects the circuit by melting and breaking the circuit if current is too high.
18. What is the direction of conventional current flow?
From positive to negative terminal.
19. Give one example where heating effect of current is used.
Electric heater.
20. Why does resistance increase with temperature?
Because atoms vibrate more, colliding more with electrons and resisting current.
Long Answer Questions (10 questions)
1. Explain the heating effect of electric current with examples.
When electric current flows through a resistor, heat is produced due to resistance. This effect is used in devices such as electric heaters, electric irons, and toasters. The heat depends on the current, resistance, and time the current flows (Formula
H = I^2Rt).
2. How does the resistance of a wire depend on its length, thickness, and material?
Resistance increases with the length of the wire because electrons collide more over longer paths. Resistance decreases with thicker wires as they provide more paths for electrons. Different materials have different resistivities affecting resistance.
3. Describe the difference between series and parallel resistors.
In series circuits, resistors are connected one after another and the same current flows through each. Their resistances add up. In parallel circuits, resistors are connected side by side, voltage across each is same, and the total resistance is less than the smallest individual resistance.
4. State and explain Ohm’s law with a suitable graph.
Ohm’s law states that the current flowing through a conductor is proportional to the voltage across it, provided temperature remains constant. The graph between voltage and current is a straight line passing through the origin.
5. What is electric power? How is it calculated?
Electric power is the rate at which electrical energy is consumed. It is calculated by the product of voltage and current:
P = VI. Using Ohm’s law, it can also be expressed as P = I^2R or P = V^2 / R.
6. Explain the use of electric circuits in daily life with examples.
Electric circuits are used to power lights, fans, appliances, and gadgets at home and in industries. They control and regulate the flow of current safely and efficiently.
7. What safety devices are used in electric circuits?
Fuses, circuit breakers, and earthing are used to prevent damage and accidents caused by excessive current.
8. How does electric energy consumption affect electricity bills?
The energy consumed in kWh (kilowatt-hours) is multiplied by the rate per unit to calculate the bill. Less consumption means lower bills.
9. What is the significance of resistors in electronics?
Resistors control current levels, divide voltage, and protect components from excess current in circuits.
10. How is a fuse rated and why is it important?
A fuse is rated by the maximum current it can safely carry. It is important to select the right rating to prevent damage or fire by breaking the circuit if current exceeds the limit.