Physical Science

236)The starting current of an electric motor is ________ the current flowing after the motor reaches its normal running speed.
exactly equal to nearly equal
much greater than less than
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237)Energy conversions in loudspeaker are
electrical to mechanical to sound mechanical to electrical to sound
sound to mechanical to electrical mechanical to sound
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238)Energy conversions taking place in microphone are
electrical to mechanical to sound sound to electrical to mechanical
sound to mechanical to electrical elsctrical to sound
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239)A transformer is used for
generating electricity converting AC to DC
stepping up (or down ) voltage None of these
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240)In our houses we get 220V ac. The value 220 represents
effective voltage constant voltage
average voltage peak voltage
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241)What is the frequency of ac current we use at houses?
25Hz 50Hz
75Hz 100Hz
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242)The advantage of AC over DC current is that
it is free from voltagefluctuations it can be transmitted over long distance with minimum power loss
it contains more electric energy production cost is less
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243)The function of fuse in an electrical circuit is
to regulate the flow of current to break the circuit in case of over loading or short circuiting
to avoid electri shocks none of these
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244)In an electrical circuit a fuse is connected
in the neutral wire in the live wire
in the earth wire anywhere
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245)If a fuse blows frequently, one should
replace it with thick wire replace it thin wire
check for fault in the circuit None of these
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246)The material used for a fuse wire should have
high melting point high resistivity
low melting point low ductility
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247)One should not connect a number of electrical appliances to the same power socket because
the appliances will not get proper current the appliances will not get proper voltage
this can damage the appliances this can damage the domestic wiring due to overheating
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248)An electrical appliance is earthed to
avoid short circuiting prevent electric shock
protect the appliance against any damage reduce consumption
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249)The filament of electric bulb is made of
lead copper
tungsten iron
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250)The filament of an electric bulb is red hot but the wires that hold the filament are slightly heated because they
have higher melting point have smaller current passing through them
are made of steel have very low resistance
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