Preview Question paper 1 (121to153)

Q.121 The function of snubber circuit is 
a.)Suppress dv/dt✔
b.)Increase dv/dt
c.)Decrease dv/dt
d.)None of these

Q.122 What is the dielectric of mica?
a.)200
b.)100
c.)3-8✔
d.)1-2

Q.123 What is the name of fluorscent material that give red colour fluorscent
a.)Zinc silicate
b.)Calcium silicate
c.)Zic silphide
d.)Magnesium silicate✔

Q.124 The noise resulting from vibration of lamination set by magnetic force is termed as 
a.) Magneto striction
b.)Boom
c.)Hum✔
d.)Zoom

Q.125 Galvanised steel is generally used as
a.)Stray wire
b.)Earth wire
c.)Structural component
d.)All of the above✔

Q.126 When R2 is rotor resistance , X2 the rotor reactance at supply frequency and s the slip, then the condition for the maximum torque under running codition will be 
a.)sR2=X2
b.)R2=s2X2
c.)R2=s2X22
d.)R2=Sx2✔

Q.127 Which of the following method are suitble for the speed control of squirrel cage induction motor
i.)Voltage contorl
ii.)Frequency control
iii.)Pole changing method
iv.)Rotor resistance control
Select the correct answer using the code given below
a.)2,3 and 4
b.)1,2 and 3✔
c.)1,3 and 4
d.)2 and 4

Q.128 In star delta starting  of an induction motor
a.)Reduce voltage is applied to the rotor
b.)Applied voltage per stator phas is 57.7% of the line voltage✔
c.)Line voltage is 57.7% of stator voltage
d.)resistance is inserted in the rotor

Q.139 Which is following methods of speed control is not affected through stator side
a.)Change of rotor resistance
b.)Change of number of pole
c.)Change of supply voltage
d.)Change of supply frequency✔

Q.130 The wound rotor type induction motor is used for ________speed operation
a.)Constant
b.)Maximum
c.)Minimum
d.)Variable✔

Q.131 Pole changing method is suitable for ______type induction motor
a.)Wound rotor
b.)squirrel cage✔
c.)linear
d.)None of these

Q.132 Buchholz's relay protect from
a.)Winding to winding fault
b.)All type of internal fault✔
c.)Turn to turn fault
d.)None of these

Q.133 A capacity of cranes is expressed in
a.)Span
b.)Type of drive
c.)Tonnes✔
d.)any of the above

Q.134 A saturable core reactor is basically a
a.)Variable resistor
b.)Step down transformer
c.)Thermal relay
d.)Variable impedence✔

Q.135 In case of contactor , overheating of contact is caused from any of the following except
a.)Excess pressure✔
b.)High induction load
c.)Copper oxide on contact
d.)Carrying load for long time

Q.136 In case of low and medium voltage circuit permissible voltage variation is 
a.)1%
b.)5%✔
c.)10%
d.)15%

Q.137 The earth potential is taken as
a.)Infinite
b.)Supply voltage
C.)1Volt
d.)Zero✔

Q.138 MIG welding is 
a.)Mild steel inert gas
b.)Medium inert gas
c.)Mximum inner depth gas welding✔
d.)Matel inert gas

Q.149 For both lap and wave windings, there are a many commutator bars as the number of 
a.)Poles
b.)Slots
c.)Armature conductor
d.)Winding element✔

Q.140 A wir of rsisitance R has its length and cross-section both doubled. Its resistance will become
a.)0.5R
b.)R✔
c.)2R
d.)4R

Q.141 5×1016 electron pass across the section of a conductor in 1 minute and 20 seconds. the current following is
a.) 0.1 mA✔
b.) 1 mA
c.) 10 mA
d.) 100 mA

Q.142 Three element having conductance G1, G2 and G3 are connected in parallel. Their combined conductance will be 
a.) (G1+G2+G3)-1
b.) G1+G2+G3✔
c.)1/G1+1/G2+1/G3
D.)(1/G1+1/G2+1/G3)-1

Q.143 Which of the following has negative temperature coefficient
a.)Electrolytes✔
b.)Brass
c.)Copper
d.)Silver

Q.144 Which of the following has positive temperature coefficient
a.)Germanium
b.)Gold✔
c.)Paper
d.)Rubber

Q.145 The substance used to slow down the speed of neutrons in a nuclear reactor during fission reaction is called
a.)Coolant
b.)Liquid
c.)Moderator✔
d.)Control element

Q.146 Stator core of an induction motor is made of
a.)Laminated cast iron
b.)mild steel
c.)Silicon steel stamping✔
d.)Softwood

Q.147 Slipring of a face wound induction motor are made of
a)Wood
b.)Steel
c.)copper✔
d.)cast iron

Q.148 There is no electrical connection between stator and rotor, still power is transferred from stator to rotor through
a.)Magnetic flux✔
b.)Air
c.)Water
d.)Magnet

Q.149 The plates of lead acid battery is made of 
a.)Rolled zic copper alloy
b.)Perforated nickel-cadmium alloy✔
c.)Cast animonial lead alloy
d.)None of these

Q.150 The lead acit battery , during charging
a.)Anod become whitish in color
b.)Voltage drop
c.)The cell give out energy
d.)Specific gravity of acid increases✔

Q.151 The condition of fully charged lead acid battery can be ascertained by
a.)Specific gravity of electrolyte
b.)Voltage
c.)Gassing
d.)Any of the above✔

Q.152 A circuit that operate in such a way thats output is high when all ita input are high
a.)OR
b.)NAND
c.)NOR
d.)AND✔

Q.153 How many input does a full adder have 
a.) 2
b.) 4
c.) 8
d.) 3✔