274. The heating element often used in an electric iron is
   (a) copper
   (b) tungsten
   (c) mica
   (d) nichrome
Ans: (d)
275. A transformer
   (a) converts direct current into alternating current
   (b) converts alternating current into direct current
   (c) steps up or steps down a given alternating current voltage
   (d) supplies current with zero resistance
Ans: (c)
276. In a dynamo
   (a) mechanical energy is converted to light energy
   (b) mechanical energy is converted to heat energy
   (c) mechanical energy is converted to electrical energy
   (d) electrical energy is converted to mechanical energy
Ans: (c)
277. In the electrical circuit of a house the fuse acts as
   (a) a thermopile
   (b) a load
   (c) a step down device
   (d) a safety device
Ans: (d)
278. In the fuse of an electrical installation blows out
   (a) replace the fuse by a thin wire
   (b) replace the fuse by a thick copper wire
   (c) replace the fuse by a fuse wire of proper rating
   (d) replace the fuse by nichrome wire
Ans: (c)
279. Commonly used safety fuse wire is made of
   (a) Tin
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