Physics · Class 10 CBSE
A student connects two identical bulbs in series with a battery. Compared to a single bulb connected to the same battery, the bulbs will glow dimmer because:
A wire of resistance 5 Ω carries a current of 2 A. What is the potential difference across the wire?
A student replaces a copper wire with another wire of the same length but double the cross-sectional area. What happens to the resistance?
Which appliance is designed to convert electrical energy mainly into heat energy?
Two resistors of 3 Ω and 6 Ω are connected in parallel. The equivalent resistance is:
A household uses a 1000 W electric heater for 2 hours. How much electrical energy is consumed?
Why are electric heaters usually made of nichrome wire?
A student observes that the ammeter reading increases when the resistance in a circuit decreases while the battery voltage remains constant. Which law explains this observation?
Which factor does not affect the resistance of a conductor?
A fuse wire melts when excessive current flows through a circuit. Why?
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Why are household appliances connected in parallel rather than in series?
2 marksState Ohm\'s Law. Mention one condition under which it is valid.
2 marksTwo wires are made of the same material. One wire is twice as long as the other but has the same cross-sectional area. Compare their resistances with a reason.
2 marksA student notices that the electricity bill increases significantly during winter. Explain this using the concept of electrical energy consumption.
2 marksDifferentiate between electric power and electrical energy.
2 marksExplain the factors affecting the resistance of a conductor. In your answer, discuss: - Length - Cross-sectional area - Nature of the material - Temperature Give suitable examples.
5 marksA circuit contains resistors connected in both series and parallel. Explain: - Rules for equivalent resistance in series. - Rules for equivalent resistance in parallel. - Advantages of parallel connections in household wiring.
5 marksCase study: A family uses the following appliances every day: - LED bulb: 20 W for 5 hours - Television: 100 W for 3 hours - Electric heater: 1000 W for 2 hours Answer the following questions: (a) Which appliance consumes the maximum electrical energy in one day?
1 markCase study: A family uses the following appliances every day: - LED bulb: 20 W for 5 hours - Television: 100 W for 3 hours - Electric heater: 1000 W for 2 hours Answer the following questions: (b) Why does the heater consume more electrical energy than the LED bulb?
1 markCase study: A family uses the following appliances every day: - LED bulb: 20 W for 5 hours - Television: 100 W for 3 hours - Electric heater: 1000 W for 2 hours Answer the following questions: (c) State the commercial unit of electrical energy.
1 markCase study: A family uses the following appliances every day: - LED bulb: 20 W for 5 hours - Television: 100 W for 3 hours - Electric heater: 1000 W for 2 hours Answer the following questions: (d) Mention one practical way the family can reduce its electricity consumption without reducing comfort significantly.
1 mark