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A transformer is used to light a 100 W and 110 V lamp from a 220 V mains. If the main current is 0.5 amp, the efficiency of the transformer is approximately
Options
(a) 50%
(b) 90%
(c) 10%
(d) 30%
Correct Answer:
90%
Explanation:
? = P output / P input x 100
= 100 / 220 x 0.5 = 90.9%
Related Questions: - If ∆U and ∆W represent the increase in internal energy and work done by the system
- The photoelectric threshold wevelength for potassium (work function being 2 eV) is
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Topics: Alternating Current
(96)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- If ∆U and ∆W represent the increase in internal energy and work done by the system
- The photoelectric threshold wevelength for potassium (work function being 2 eV) is
- A nucleus at rest splits into two nuclear parts having radii in the ratio 1:2.
- A source is moving towards an observer with a speed of 20 m/s and having frequency
- A rectangular copper coil is placed in a uniform magnetic field of induction 40 mT
Topics: Alternating Current (96)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
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