Electricity (Case Study) (10 Science)
Case-based questions on electric circuits, current, resistance, and power. Real-world applications in household wiring and electrical safety.
TL;DR: Case-based questions on electric circuits, current, resistance, and power. Real-world applications in household wiring and electrical safety.
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
Case-based questions on electric circuits, current, resistance, and power. Real-world applications in household wiring and electrical safety.
Electricity (Case Study) MCQs with Answers & Explanations
Q1. A house has a 5 A fuse and operates at 230 V. A resident connects a 1000 W heater, 500 W oven, and 100 W light simultaneously. Will the fuse blow? (Calculate power consumed)
- No, total 1100 W is safe
- Yes, total 1600 W exceeds fuse capacity ✓ (correct)
- No, fuses only regulate current
- Cannot determine without resistance values
Q2. Three resistors of 6 ohms, 6 ohms, and 12 ohms are connected in a circuit. Two 6-ohm resistors are in parallel, then this combination is in series with the 12-ohm resistor. What is the total resistance?
- 3 ohms
- 9 ohms ✓ (correct)
- 15 ohms
- 24 ohms
Q3. A copper wire has a resistance of 5 ohms at 20°C. As temperature increases to 100°C, the resistance increases due to thermal motion of electrons. What happens to the conductivity of copper?
- Increases
- Decreases ✓ (correct)
- Remains constant
- Becomes zero
Q4. An ammeter has a low resistance (nearly zero) while a voltmeter has high resistance. Why must an ammeter be connected in series and a voltmeter in parallel?
- To prevent voltage drops across ammeter
- To ensure accurate measurement of current and voltage respectively ✓ (correct)
- To avoid damaging the instruments
- There is no specific reason
Q5. A circuit has a 12 V battery, a switch, a 4-ohm resistor, and an ammeter. When the switch is closed, the ammeter reads 2.5 A. What is the internal resistance of the battery?
- 0.4 ohms
- 0.8 ohms ✓ (correct)
- 1.6 ohms
- 2.0 ohms
Q6. A light bulb rated 60 W, 120 V is used in a 240 V circuit with an appropriate series resistor for protection. What is the power consumed by the series resistor?
- 20 W
- 30 W
- 60 W
- 90 W ✓ (correct)
Q7. In a parallel circuit with three identical bulbs rated 100 W each at 230 V, if one bulb burns out, what happens to the brightness of the remaining bulbs?
- Increases
- Decreases
- Remains same ✓ (correct)
- Becomes zero
Q8. A heating element of resistance 10 ohms carries a current of 2 A for 5 minutes. How much heat is produced?
- 100 J
- 1000 J
- 6000 J
- 12000 J ✓ (correct)
Frequently Asked Questions
What is the difference between an electric fuse and a circuit breaker?
A fuse is a one-time protective device that melts when current exceeds its rating, breaking the circuit. A circuit breaker is a reusable automatic switch that trips when overloaded and can be reset. Fuses provide overcurrent protection but require replacement, while breakers offer convenience and can be switched manually.
Why does a thicker wire have lower resistance than a thin wire of the same material and length?
Resistance is given by R = rho * L / A, where A is the cross-sectional area. A thicker wire has a larger area A, so resistance is inversely proportional to area. More material allows charge carriers more pathways, reducing opposition to current flow.
More 10 Science MCQs
- Light Reflection and Refraction
- Electricity
- Acids Bases and Salts
- Life Processes
- Carbon and its Compounds
- Metals and Non-metals
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