InterviewSolution
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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
A student carries out an experiment and plots the V-I graph of three samples of nichrome wire with resistances R1, R2 and R3 respectively (Figure.12.5). Which of the following is true?(a) R1 = R2 = R3(b) R1 > R2 > R3(c) R3 > R2 > R1(d) R2 > R3 > R1 |
| Answer» (c) R3 > R2 > R1 | |
| 2. |
How will you conclude that the same potential difference (voltage) exists across three resistors connected in a parallel arrangement to a battery? |
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Answer» Hint— Describe the experiment using a circuit diagram. Give details showing that same potential difference exists across each resistance in a parallel circuit. |
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| 3. |
How does use of a fuse wire protect electrical appliances? |
| Answer» If a current larger than a specified value flows in a circuit, temperature of fuse wire increases to its melting point. The fuse wire melts and the circuit breaks. | |
| 4. |
Three incandescent bulbs of 100 W each are connected in series in an electric circuit. In another circuit another set of three bulbs of the same wattage are connected in parallel to the same source.(a) Will the bulb in the two circuits glow with the same brightness? Justify your answer.(b) Now let one bulb in both the circuits get fused. Will the rest of the bulbs continue to glow in each circuit? Give reason. |
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Answer» (a) No. The resistance of the bulbs in series will be three times the resistance of single bulb. Therefore, the current in the series combination will be one-third compared to current in each bulb in parallel combination. The parallel combination bulbs will glow more brightly. (b) The bulbs in series combination will stop glowing as the circuit is broken and current is zero. However the bulbs in parallel combination shall continue to glow with the same brightness. |
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| 5. |
B1, B2 and B3 are three identical bulbs connected as shown in Figure 12.8. When all the three bulbs glow, a current of 3A is recorded by the ammeter A.(i) What happens to the glow of the other two bulbs when the bulb B1 gets fused?(ii) What happens to the reading of A1, A2, A3 and A when the bulb B2 gets fused?(iii) How much power is dissipated in the circuit when all the three bulbs glow together |
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Answer» Hint— (i) The glow of the bulbs B2 and B3 will remain the same. |
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| 6. |
(a) same current flowing through them when connected in parallel(b) same current flowing through them when connected in series(c) same potential difference across them when connected in series(d) different potential difference across them when connected in parallel |
| Answer» (b) same current flowing through them when connected in series | |
| 7. |
(a) volt ampere(b) kilowatt hour(c) watt second(d) joule second |
| Answer» (a) volt ampere | |
| 8. |
In an electrical circuit three incandescent bulbs A, B and C of rating 40 W, 60 W and 100 W respectively are connected in parallel to an electric source. Which of the following is likely to happen regarding their brightness?(a) Brightness of all the bulbs will be the same(b) Brightness of bulb A will be the maximum(c) Brightness of bulb B will be more than that of A(d) Brightness of bulb C will be less than that of B |
| Answer» (c) Brightness of bulb B will be more than that of A | |
| 9. |
In an electrical circuit two resistors of 2 Ω and 4 Ω respectively are connected in series to a 6 V battery. The heat dissipated by the 4 Ω resistor in 5 s will be(a) 5 J(b) 10 J(c) 20 J(d) 30 J |
| Answer» (c) 20 J is The heat dissipated by the 4 Ω resistor in 5 s | |
| 10. |
The proper representation of series combination of cells (Figure 12.4) obtaining maximum potential is |
| Answer» (a) (i) The proper representation of series combination of cells | |
| 11. |
(a) (i)(b) (ii)(c) (iii)(d) (iv) |
| Answer» (b) (ii) electrical components have been properly connected. | |
| 12. |
(a) 1/5 Ω(b) 1/25 Ω(c) 1/10 Ω(d) 25 Ω |
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Answer» Minimum resistance is observed when they are connected in parallel (you can take it as a thumb rule that the resistance of a group of resistors connected in parallel will be less then the minimum resistance present in the group) thus net resistance 1/R = 1/R1 + 1/R2 + .... and so it can be calculated to be 1/25 (b) 1/25 Ω is the minimum resistance |
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| 13. |
(a) 1/5 Ω(b) 10 Ω(c) 5 Ω(d) 1 Ω |
| Answer» (d) 1 Ω is the maximum resistance | |
| 14. |
Should the resistance of an ammeter be low or high? Give reason. |
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Answer» It should be as close to zero as possible. Ideally it should be zero ohm. If it is non-zero and substantial it will affect the true current |
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| 15. |
(a) same in all the cases(b) minimum in case (i)(c) maximum in case (ii)(d) maximum in case (iii) |
| Answer» (a) same in all the cases | |
| 16. |
(a) maximum in (i)(b) maximum in (ii)(c) maximum in (iii)(d) the same in all the cases |
| Answer» (b) maximum in (ii) | |