Q.1
A current density of _________ is used for large power transformers with forced circulation of oil or with water cooling coils
  • 1.5 to 2.5 A/mm²
  • 3.5 to 4.5 A/mm²
  • 4.0 to 5.0 A/mm²
  • 5.4 to 6.2 A/mm²
Q.2
In a Weston frequency meter, the magnetic axes of the two fixed coils are
  • parallel
  • perpendicular
Q.3
Which of the following methods is used for air cooling of turbo-alternators ?
  • One sided axial ventilation
  • Two sided axial ventilation
  • Multiple inlet system
  • All of the above
Q.4
A Weston synchronoscope is a
  • moving coil instrument
  • moving iron instrument
  • dynamometer instrument
  • none of the above
Q.5
To measure a resistance with the help of a potentiometer it is
  • necessary to standardise the potentiometer
  • not necessary to standardise the potentiometer
  • necessary to use a volt ratio box in conjunction with the potentiometer
  • none of the above
Q.6
Wattmeter cannot be designed on the principle of
  • electrostatic instrument
  • thermocouple instrument
  • moving iron instrument
  • electrodynamic instrument
Q.7
In a 3-phase power measurement by two wattmeter method the reading of one of the wattmeter was zero. The power factor of the load must be
  • unity
  • 0.5
  • 0.3
  • zero
Q.8
If the current in a capacitor leads the voltage by 80°, the loss angle of the capacitor is
  • 10°
  • 80°
  • 120°
  • 170°
Q.9
In a dynamometer 3-phase power factor meter, the planes of the two moving coils are at
  • 0°
  • 60°
  • 90°
  • 120°
Q.10
In Weston synchronoscope the moving coil is connected across
  • bus-bars
  • incoming alternator
  • fixed coils
  • any of the above
Q.11
Which of the following instruments indicate the instantaneous value of the electrical quantity being measured at the time at which it is being measured ?
  • Absolute instruments
  • Indicating instruments
  • Recording instruments
  • Integrating instruments
Q.12
A phase shifting transformer is used in conjunction with
  • potentiometer
  • Drysdale potentiometer
  • co-ordinate potentiometer
  • Crompton potentiometer
Q.13
An instrument transformer is used to extend the range of
  • induction instrument
  • electrostatic instrument
  • moving coil instrument
  • any of the above
Q.14
According to Lenz law write the formula for finding emf induced in the coil?
  • B=ϕ÷AB=\phi\div AB=ϕ÷A
  • E=−dϕdtE=-\frac{\text{d}\phi}{\text{dt}}E=−dtdϕ​
  • H=MMFLH=\frac{MMF}{L}H=LMMF​
  • MMM=NIMMM=NIMMM=NI
Q.15
How will you find the magnetic field strength?
  • B=ϕ÷AB=\phi\div AB=ϕ÷A
  • E=dϕdtE=\frac{\text{d}\phi}{\text{dt}}E=dtdϕ​
  • H=MMFLH=\frac{MMF}{L}H=LMMF​
  • MMM=NIMMM=NIMMM=NI
Q.16
How will you find the magnetic flux density?
  • B=ϕ÷AB=\phi\div AB=ϕ÷A
  • E=dϕdtE=\frac{\text{d}\phi}{\text{dt}}E=dtdϕ​
  • H=MMFLH=\frac{MMF}{L}H=LMMF​
  • MMM=NIMMM=NIMMM=NI
Q.17
Write the formula for finding mmf?
  • B=ϕ÷AB=\phi\div AB=ϕ÷A
  • E=dϕdtE=\frac{\text{d}\phi}{\text{dt}}E=dtdϕ​
  • H=MMFLH=\frac{MMF}{L}H=LMMF​
  • mmf=NImmf=NImmf=NI
Q.18
Write the formula for finding emf induced in the coil?
  • B=ϕ÷AB=\phi\div AB=ϕ÷A
  • E=dϕdtE=\frac{\text{d}\phi}{\text{dt}}E=dtdϕ​
  • H=MMFLH=\frac{MMF}{L}H=LMMF​
  • MMM=NIMMM=NIMMM=NI
Q.19
What is the relationship between the VA rating of a transformer and the internal percentage impedance Z?
  • VA ∝1/ Z
  • VA ∝Z
  • VA ∝2Z
  • VA ∝ Z/2
Q.20
How can the direction of a capacitor start single phase motor be reversed?
  • Reverse the connection to the capacitor
  • Reverse the connection to the start winding
  • Reverse the polarity of the supply
  • Reverse the connection of the start and run windings
0 h : 0 m : 1 s