Measurements and Instrumentation - Section 1 (3)
Measurements and Instrumentation - Section 1
| 17. | Assertion (A): A hot wire ammeter has a cramped scale. Reason (R): The heat is proportional to square of current. |
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Answer: Option A Explanation: Since heating ∝ I2, scale is cramped. |
| 18. | Potentiometer method of dc voltage measurement is more accurate than direct measurement using a voltmeter because |
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Answer: Option C Explanation: Since the circuit is not loaded, the accurate value of dc voltage is measured. |
| 19. | A moving coil instrument has a resistance of 0.5 Ω and a full scale deflection of 0.1 A. To convert it into an ammeter of 0-10 A the shunt resistance should be |
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| 20. | A full wave rectifier type meter is used to measure the wave shape shown in figure. The voltmeter is calibrated to read rms value of sine wave. The reading of voltmeter will be |
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Answer: Option D Explanation: Peak value of sine wave = 100 x 1.11 = 111 V. |
| 21. | A standard cell of 1.0185 V is used with a slide wire potentiometer. The balance was obtained at 60 cm. When an unknown emf was connected, the balance was obtained at 82 cm. The magnitude of unknown emf is |
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| 22. | The household energy meter is |
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Answer: Option C Explanation: It integrates energy over a period of time. |
| 23. | In a resistance strain gauge, G = 2, stress = 1050 kg/cm2, R = 1000 Ω. The value of ΔR will be |
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| 24. | A meter with a resistance of 100 Ω and a full scale deflection of current of 1 mA is to be converted into voltmeter of 0 - 5 V range. The multiplier resistance should be |
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