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Electricity

99 MCQ questions with answers and explanations · page 4 of 4

Q76. battery converts...........energy into electrical energy.

  1. Aheat
  2. Bmechanical
  3. Cchemical
  4. DLight
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Answer: C) chemical

Q77. The device that converts alternating current into direct current is called-

  1. AInverters
  2. BRectifier
  3. Ctransformer
  4. Dtransmitter
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Answer: B) Rectifier

Q78. Transformers are used in-

  1. ATo convert AC to DC
  2. BTo convert DC to AC
  3. CTo oxidize DC voltage
  4. DTo oxidize or reduce AC voltage
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Answer: D) To oxidize or reduce AC voltage

Q79. The most commonly used substance in fluorescent tubes is

  1. Asodium oxide and argon
  2. Bsodium vapor and neon
  3. Cmercury vapor and argon
  4. Dmercuric oxide and neon
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Answer: C) mercury vapor and argon

Q80. In a three pin electrical plume the longest pin should be connected to-

  1. Afrom the base end
  2. BSanjeev from the beginning
  3. Cfrom an indifferent head
  4. Dfrom any end
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Answer: A) from the base end

Q81. The value of one kilowatt hour (kWh) is-

  1. A36×10 6J
  2. B3.6×103J
  3. C100 J
  4. D10 J
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Answer: A) 36×10 6J

Q82. house has two bulbs, one of which gives more light than the other. Which of the following statements is correct?

  1. AThe brightness of the light does not depend on the resistance
  2. BBoth bulbs have the same resistance
  3. CThe resistance of the bulb with more light is higher
  4. DDim light bulbs have higher resistance.
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Answer: C) The resistance of the bulb with more light is higher

Q83. What is the purpose of choke in fluorescent lamp?

  1. Areducing the flow of current
  2. Bincrease the flow of current
  3. Creduce resistance
  4. DMomentary voltage reduction
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Answer: C) reduce resistance

Q84. The electrical resistance of a conductor is independent of

  1. Atemperature
  2. Bpressure
  3. Ccross-sectional area
  4. Dlength
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Answer: B) pressure

Q85. If the electrical resistance of a typical substance drops to zero, what is that substance called?

  1. Asuperconductor
  2. Bsemiconductor
  3. CDriver
  4. Danti-inflammatory
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Answer: A) superconductor

Q86. If a resistive wire is made longer, then its resistance-

  1. Aincreases
  2. Bdecreases
  3. Cremains constant
  4. DAll of these
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Answer: A) increases

Q87. Electricity resides in mercury lamp-

  1. Amercury at low pressure
  2. Bmercury at high pressure
  3. CNeon and mercury
  4. Dnone of these
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Answer: A) mercury at low pressure

Q88. The device used to change the speed of an electric fan is-

  1. Aamplifier
  2. Bregulator
  3. CSwitch
  4. DRectifier
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Answer: B) regulator

Q89. The MCB which cuts off the power supply in case of a short circuit works by—

  1. AOn the magnetic effect of current
  2. Belectroplating effect of current
  3. COn the chemical effects of current
  4. DOn the heating effect of current
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Answer: D) On the heating effect of current

Q90. How much is 1 volt equal to?

  1. A1 joule
  2. B1 joule/coulomb
  3. C1 newton coulomb
  4. D1 joule/newton
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Answer: B) 1 joule/coulomb

Q91. When a soap bubble is charged, then-

  1. AIt shrinks,
  2. BIt spreads
  3. CThere is no change in its size
  4. Dnone of the above
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Answer: B) It spreads

Q92. Dynamo is a machine whose function is-

  1. Aconverting high voltage to low
  2. Bconverting low voltage to high
  3. Cconverting electrical energy into mechanical energy
  4. Dconverting mechanical energy into electrical energy
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Answer: D) converting mechanical energy into electrical energy

Q93. A current carrying conductor is related to-

  1. Afrom the magnetic field
  2. Bfrom the electric field
  3. Cfrom the electromagnetic field
  4. Dfrom the electrostatic field
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Answer: C) from the electromagnetic field

Q94. Which instrument measures electrical resistance?

  1. AAmmeter
  2. Bpotentiometer
  3. Cvoltameter
  4. Dohm meter
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Answer: D) ohm meter

Q95. The instrument used to detect the presence of electric current in a circuit is-

  1. Arefractometer
  2. Bgalvanometer
  3. Cviscometer
  4. Ddiffractometer
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Answer: B) galvanometer

Q96. The cost of energy to operate an industrial refrigerator that uses 5 kW of power when it operates for 10 hours a day for 30 days is [given that the charge per kWh of energy is ₹4]

  1. A₹ 600
  2. B₹ 6,000
  3. C₹ 1,200
  4. D₹ 1,500
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Answer: B) ₹ 6,000

Q97. When a short circuit condition occurs, the current in the circuit-

  1. Abecomes zero
  2. Bremains stable
  3. Cgrows sufficiently
  4. Dchanges randomly
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Answer: C) grows sufficiently

Q98. A metallic wire having a resistance of 200 Ω is cut lengthwise into two equal parts and then these parts are connected in parallel. What is the resistance of this parallel combination equal to?

  1. A1Ω
  2. B10Ω
  3. C5 ohms
  4. D15Ω
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Answer: C) 5 ohms

Q99. Faraday's constant-

  1. Adepends on the amount of electrolyte
  2. Bdepends on the electric current passed through the electrolyte
  3. CDepends on the volume of the solvent in which the electrolyte is dissolved.
  4. Dis a universal constant (e) None of the above More than one of the above
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Answer: D) is a universal constant (e) None of the above More than one of the above

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