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An electric motor operating on a 60 volt D.C supply draws a current of 10 amp. If the efficiency of the motor is 50%, the resistance of its windings is
Options
(a) 3 ohm
(b) 6 ohm
(c) 15 ohm
(d) 30 ohm
Correct Answer:
3 ohm
Explanation:
Efficiency n = 50 %
e = E/2 ⇒ I = (E – e) / R = [E – (E/2)] / RA = E / 2R
10 = 60 / 2R ⇒ R = 60 / (2 × 10) = 3 ohm
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Topics: Current Electricity
(136)
Subject: Physics
(2479)
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