Electricity (Class 10 Science)
Electricity is the flow of electrons through a conductor, and understanding electric current, resistance, and power is crucial for practical applications.
TL;DR: Electricity is the flow of electrons through a conductor, and understanding electric current, resistance, and power is crucial for practical applicati…
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
Electricity is the flow of electrons through a conductor, and understanding electric current, resistance, and power is crucial for practical applications.
Electricity MCQs with Answers & Explanations
Q1. The SI unit of electric current is:
- Volt
- Coulomb
- Ampere ✓ (correct)
- Ohm
Explanation: The SI unit of electric current is Ampere, which is the flow of one coulomb of charge per second through a conductor.
Q2. According to Ohm's law, V = IR. What does R represent?
- Resonance
- Refraction
- Reactance
- Resistance ✓ (correct)
Explanation: R represents resistance, which is the opposition offered by a conductor to the flow of electric current through it.
Q3. When resistors are connected in series, the total resistance is:
- Equal to the sum of individual resistances ✓ (correct)
- Less than the smallest resistance
- Less than the largest resistance
- Equal to the reciprocal of the sum
Explanation: In a series circuit, the total resistance equals the sum of all individual resistances: R_total = R1 + R2 + R3 + ...
Q4. The equivalent resistance of three 6-ohm resistors connected in parallel is:
- 6 ohms
- 2 ohms ✓ (correct)
- 0.5 ohms
- 18 ohms
Explanation: For resistors in parallel: 1/R_eq = 1/6 + 1/6 + 1/6 = 3/6, so R_eq = 2 ohms.
Q5. The heating effect of electric current is known as:
- Joule heating
- Ohmic heating
- Thermal heating
- All of the above ✓ (correct)
Explanation: The heating effect of current is known as Joule heating, Ohmic heating, or thermal heating - all terms are used interchangeably.
Q6. What is the power consumed by a 100-watt bulb operated for 10 hours?
- 10 watt-hours
- 1 kilowatt
- 1000 watt-hours ✓ (correct)
- 100 watt-hours
Explanation: Energy consumed = Power x Time = 100 W x 10 h = 1000 watt-hours or 1 kilowatt-hour.
Q7. The SI unit of electrical energy is:
- Watt
- Coulomb
- Volt
- Joule ✓ (correct)
Explanation: The SI unit of electrical energy is Joule, which equals one watt-second of power consumption.
Q8. Which of the following materials is a good conductor of electricity?
- Copper ✓ (correct)
- Plastic
- Glass
- Rubber
Explanation: Copper is an excellent conductor of electricity due to its abundant free electrons, while rubber, glass, and plastic are insulators.
Q9. The direction of conventional current is:
- From negative to positive terminal
- From positive to negative terminal ✓ (correct)
- From negative to positive in external circuit
- In both directions simultaneously
Explanation: Conventional current is defined as flowing from the positive terminal to the negative terminal of a cell in the external circuit.
Q10. If the voltage across a conductor is doubled while its resistance remains constant, the current will:
- Be halved
- Remain the same
- Be doubled ✓ (correct)
- Be quadrupled
Explanation: According to Ohm's law, I = V/R. If voltage is doubled and resistance is constant, current is also doubled.
Frequently Asked Questions
Why do electric wires get hot when current flows through them?
Wires get hot due to Joule heating, caused by the resistance of the wire to the flow of electrons, converting electrical energy to heat.
What is the difference between AC and DC current?
DC current flows in one direction continuously, while AC current periodically reverses direction.
More Class 10 Science MCQs
- Light Reflection and Refraction
- Acids Bases and Salts
- Life Processes
- Carbon and its Compounds
- Metals and Non-metals
- Matter in Our Surroundings
🤖 Stuck on any of these? Ask Syllab's free AI Tutor to explain step by step →