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Physical Science |
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| 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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