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dc motor

Total questions: 11

Worksheet time: 6mins

Name
Class
Date
1.

In a DC Motor, the coil of the rotor turns into an electromagnet when

a)

the rotor rotates inside the stator

b)

electricity (current) flows through the coil

c)

the rotor is turned by the axle

d)

the it sits int the field of the stator

2.

The part of an electric motor that doesn't spin is called the...

a)

armature

b)

commutator

c)

stator

d)

bearings

3.

A coil carries a current in a magnetic field. The coil experiences a turning effect.

Which device uses this effect?

a)

a DC motor

b)

an electromagnet

c)

a relay

d)

a transformer

4.

How do u obtain desired speed of an armature controlled DC motor ?

a)

by varying armature current

b)

by varying the armature voltage

c)

by varying emf

d)

by varying transformer voltage

5.

Which factors not

affecting the speed of dc motors?

a)

Flux

b)

Current

c)

Applied voltage.

d)

Voltage across the armature

6.

GENERATOR CONVERTS ------ ENERGY INTO ----- ENERGY

a)

MECHANICAL, ELECTRICAL

b)

ELECTRICAL, MECHANICAL

c)

POTENTIAL,KINETIC

7.

BACK EMF OF DC MOTOR IS----------

a)

Eb = PΦNZ / 60A

b)

EB = PΦN / 60AZ

c)

EB = PΦZ / 120AN

8.

WHAT IS BACK EMF?

a)

THE VOLTAGE OPPOSES THE SUPPLY VOLTAGE

b)

THE VOLTAGE DOES NOT OPPOSE THE SUPPLY VOLTAGE

c)

SUPPLY VOLTAGE

9.

WHAT IS TORQUE?

a)

TWISTING FORCE

b)

KINETIC FORCE

c)

MAGNETIC FORCE

10.

WHICH DEVICE IS CONSTRUCTION-WISE THE SAME AS DC MOTOR?

a)

DC GENERATOR

b)

TRANSFORMER

c)

INDUCTOR

11.

THE WORKING PRINCIPLE OF DC MOTOR IS---------

a)

MUTUAL INDUCTION

b)

FLEMING'S RIGHT HAND

c)

LORENTZ LAW