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If voltage across a bulb rated 220 volt-100 Watt drops by 2.5% of its rated value, the percentage of the rated value by which the power would decrease is:
Options
(a) 20%
(b) 2.50%
(c) 5%
(d) 10%
Correct Answer:
5%
Explanation:
Resistance of bulb is constant
P = V² / R
∆p / p = 2∆V / V + ∆R / R
∆p / P = 2 x 2.5 + 0 = 5%
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Topics: Current Electricity
(136)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- A bar magnet is hung by a thin cotton thread in a uniform horizontal magnetic field
- If longitudinal strain for a wire is 0.03 and its poisson’s ratio is 0.5
- Electrons of mass m with de-Broglie wavelength λ fall on the target in an X-ray tube.
- Core of electromagnets are made of ferromagnetic material which has
- If light emitted from sodium bulb is passed through sodium vapour,
Topics: Current Electricity (136)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
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