Technical Quiz Round-2

The back emf of a dc motor depends on

• Field flux

• Shape of conductors

• Type of slip rings

• Brush material

The back emf of dc motor depends on

• Armature speed N

• Field flux ɸ

• Number of armature conductors

• All of these

In a dc machine prominent and noisy blue and green sparks indicate

• Excessive brush wear

• Winding fault

• Worn out insulation

• None of these

Frog leg winding is____?

• Same as simplex winding

• Same as duplex winding

• Combined lap and wave windings on a single rotor

• Duplex wave winding on a single rotor

The flux is maximum in following unit of a dc motor

• Yoke leading end of pole shoe

• Trailing end of pole shoe

• Yoke

• Any of the above

The direction of rotation of a dc motor can be reversed by reversing the connection to

• Armature

• Series field

• Shunt field

• Any of the above

The current flowing in conductors of a dc motor is

• AC

• DC

• AC as well as DC

• Transient

When an electric train is moving down a hill the dc motor acts as

• Dc series motor

• Dc shunt motor

• Dc series generator

• Dc shunt generator

Which among the following is a positively charged particle emitted by a radioactive element?

• Beta ray

• Alpha ray

• Cathode ray

• Gamma ray

Isotopes are separated by

• crystallization

• sublimation

• distillation

• filtration