Q21
A 120 V lamp-dimming circuit is controlled by a rheostat and protected from excessive current by a 3 A fuse. To what minimum resistance value can the rheostat be set without blowing the fuse? Assume a lamp resistance of 20 ohms.
A.
40 Ω
B.
4 Ω
C.
2 Ω
D.
20 Ω
AnswerAnswer: Option D
Solution
Answer: Option D
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