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Worksheets20EE2E55-EMD-SQ1
Total questions: 10
Worksheet time: 5mins
The unit of magnetic flux density is ___________.
AT/Wb
Wb/AT
Wb/m2
AT/m
In DC generators, lap connected winding is used for _______ voltage and ______ current applications.
low, low
low, high
high, high
high, low
The _________ loss is directly proportional to square of frequency.
eddy current
hysteresis
variable
copper
Commutator of DC machines is made up of __________.
aluminum
silver
copper
carbon
The direction of DC motor is given by _________ rule.
Lenz’s law
Flemming’s right hand rule
Ampere’s law
Flemming’s left hand rule
Magnetically induced EMF is caused by______________
Variation in magnetic flux
Static magnetic field
Magnetic field due to moving charges
Magnetic field due to permanent magnets
The force experienced by a current-carrying conductor in a magnetic field is _________.
Lorentz force
electrostatic force
gravitational force
nuclear force
The property of the material which opposes the creation of magnetic flux is known as _______.
resistance
conductance
permeance
reluctance
A 230V DC motor takes armature current of 2.5A and runs at 1000rpm. If the resistance of armature is 0.25Ω, then the back emf developed is _________.
229 V
231 V
243 V
257 V
A 4-pole machine has an armature with 80 slots and 8 conductors/slot and runs at 1500rpm, the flux per pole is 0.05 Wb. If the winding is wave connected, the induced emf is _______.
1500V
1800V
1700 V
1600V
