1) Buzzer in principle is a bell
a. with hammer
b. with gong
c. with both hammer and gong
d. without hammer and gong
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2) In telegraphic machine, the machine parts that sends the message and the machine parts that receives the message are
a. Morse key, Morse key
b. Morse key, Morse sounder
c. Morse sounder, Morse key
d. Morse sounder, Morse sounder
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3) Electric heaters is made up of
a. Chromed iron
b. Brass
c. Steel
d. Both (a) and (b)
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4) Heating element of electric iron box is an alloy of
a. Copper and nickel
b. Nickel and cobalt
c. Iron and magnesium
d. Nickel and chromium
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5) The handle of iron box is made up of
a. Bakelite
b. Ebonite
c. Chromium
d. Only (a) and (b)
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6) In leclanche cell, anode is packed in a porous pot containing
a. manganese dioxide
b. charcoal powder
c. sulphur dioxide
d. only (a) and (b)
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7) The emf of the dry cell is about
a. 0 V
b. 0.5 V
c. 1 V
d. 1.5 V
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8) In lead acid accumulators, the container is filled with distilled water and concentrated sulphuric acid in the ratio of
a. 1 : 2
b. 2 : 1
c. 3 : 1
d. 1 : 3
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9) The positive plates of nickel iron cell is made up of
a. Nickel hydroxide
b. Lead peroxide
c. Ferrous hydroxide
d. Potassium hydroxide
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10) Lithium cells operates ranging from
a. -25 ° C to 25 ° C
b. -50 ° C to 25 ° C
c. -50 ° C to 75 ° C
d. -75 ° C to 75 ° C
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11) 3 - point starter is used to start the
a. Series motor
b. Shunt motor
c. Compound motor
d. Only (b) and (c)
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12) The overload release protects the motor against
a. Over voltage
b. Over current
c. Over load
d. All of these
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13) In four - point starter, the no volt release is connected across the
a. Supply line through a protective resistance
b. In series with field circuit through a protective resistance
c. Either (a) or (b)
d. None of these
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14) In DOL fuses are provided to protect against
a. Short circuit protection
b. Over voltage
c. Over current
d. Over load
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15) If induction motor is direct switched-on then it will develop
a. 1.5 times their full load torque
b. 1.5 to 2.5 times their full load torque
c. 2.5 times their full load torque
d. 1.5 to 5 times their full load torque
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16) Impurities are generally added in the pure semiconductor to
a. increase the number of electrons
b. increase the number of holes
c. increase their conductivity
d. all of these
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17) In N - type semiconductor, the impurities added to a semiconductor are
a. Trivalent
b. Pentavalent
c. Monovalent
d. Tetravalent
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18) The P - type semiconductor impurities are also called as
a. Acceptor impurities
b. Donor impurities
c. Either (a) or (b)
d. None of these
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19) The cut - in voltage for silicon and germanium are
a. 0.3 V, 0.3 V
b. 0.3 V, 0.7 V
c. 0.7 V, 0.7 V
d. 0.7 V, 0.3 V
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20) Filters are used to convert
a. Pulsating dc signal into a pure dc signal
b. Pure dc signal into a pulsating dc signal
c. Pulsating dc signal into a pure ac signal
d. Pulsating ac signal into a pure dc signal
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