(a) (i) What is meant by resistance of a conductor? Define its SI unit.
(ii) List two factors on which the resistance of a rectangular conductor depends.
(iii) How will the resistance of a wire be affected if its (1) length is doubled, and (2) radius is also doubled? Give justification for your answer.
OR
(b) In an electric circuit three bulbs of 100 W each are connected in series to a source. In another circuit set of three bulbs of the same wattage are connected in parallel to the same source.
(i) Will the bulb in the two circuits glow with the same brightness? Justify your answer.
(ii) Now, let one bulb in both the circuits get fused. Will the rest of the bulbs continue to glow in each circuit? Give reason for your answer.
(a) (i) What is meant by resistance of a conductor? Define its SI unit.
(ii) List two factors on which the resistance of a rectangular conductor depends.
(iii) How will the resistance of a wire be affected if its (1) length is doubled, and (2) radius is also doubled? Give justification for your answer.
OR
(b) In an electric circuit three bulbs of 100 W each are connected in series to a source. In another circuit set of three bulbs of the same wattage are connected in parallel to the same source.
(i) Will the bulb in the two circuits glow with the same brightness? Justify your answer.
(ii) Now, let one bulb in both the circuits get fused. Will the rest of the bulbs continue to glow in each circuit? Give reason for your answer.
(a) (i) Resistance of a conductor is the opposition offered by the conductor to the flow of current. Its SI unit is ohm (Ω).
(ii) The resistance of a rectangular conductor depends on its length and area of cross-section.
(iii) If the length of the wire is doubled, the resistance will also double. If the radius is also doubled, the area of cross-section will increase four times, resulting in a decrease in resistance to one fourth of its initial value.
OR
(b) (i) No, the bulbs in the two circuits will not glow with the same brightness. The bulbs in the series circuit will glow with the same brightness, while the bulbs in the parallel circuit will glow with different brightness.
(ii) No, the rest of the bulbs will not continue to glow in the series circuit. In the parallel circuit, the rest of the bulbs will continue to glow.
Marking Scheme
- 1(a) (i) /2 for defining resistance and its SI unit
- 2(a) (ii) /1 for listing factors affecting resistance
- 3(a) (iii) /2 for explaining the effect of doubling length and radius
- 4OR
- 5(b) (i) /2 for comparing brightness in series and parallel circuits
- 6(b) (ii) /2 for explaining the effect of one bulb getting fused
Hint
Use the concepts of resistance, series and parallel circuits to answer the questions.
Quick Oral Answer
(a) Resistance is the opposition to the flow of current, measured in ohms (Ω). It depends on length and area of cross-section. OR (b) In a series circuit, bulbs glow with the same brightness, while in a parallel circuit, they glow with different brightness.
Analysis & Explanation
(a) (i) Resistance is the opposition to the flow of current, measured in ohms (Ω).
(ii) The factors affecting resistance are length and area of cross-section.
(iii) Doubling the length doubles the resistance, while doubling the radius decreases the resistance to one fourth.
OR
(b) (i) In a series circuit, the bulbs glow with the same brightness, while in a parallel circuit, they glow with different brightness.
(ii) In a series circuit, if one bulb gets fused, the rest of the bulbs will not glow. In a parallel circuit, the rest of the bulbs will continue to glow.
Common Mistakes
- 1Incorrectly defining resistance
- 2Forgetting to consider the factors affecting resistance
- 3Incorrectly analyzing the effect of doubling length and radius
Interesting Facts
Resistance is a fundamental property of materials
Series and parallel circuits have different applications
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Frequently Asked Questions
How many marks does this question carry in CBSE Class 10 Science 2023?
This question carries 5 marks in the CBSE Class 10 Science 2023 examination.
Which chapter does this question come from in Science?
This question is from the chapter "Electricity" in the CBSE Class 10 Science syllabus.
What topic does this question cover in Science?
This question covers the topic "Electric Current and Circuit" from CBSE Class 10 Science.
What type of question is this in the CBSE Class 10 Science 2023 paper?
This is a Long Answer question from Section Section D in the CBSE Class 10 Science 2023 paper.