EMF and Torque MCQs

Welcome to our comprehensive collection of Multiple Choice Questions (MCQs) on EMF and Torque, a fundamental topic in the field of DC Machines. Whether you're preparing for competitive exams, honing your problem-solving skills, or simply looking to enhance your abilities in this field, our EMF and Torque MCQs are designed to help you grasp the core concepts and excel in solving problems.

In this section, you'll find a wide range of EMF and Torque mcq questions that explore various aspects of EMF and Torque problems. Each MCQ is crafted to challenge your understanding of EMF and Torque principles, enabling you to refine your problem-solving techniques. Whether you're a student aiming to ace DC Machines tests, a job seeker preparing for interviews, or someone simply interested in sharpening their skills, our EMF and Torque MCQs are your pathway to success in mastering this essential DC Machines topic.

Note: Each of the following question comes with multiple answer choices. Select the most appropriate option and test your understanding of EMF and Torque. You can click on an option to test your knowledge before viewing the solution for a MCQ. Happy learning!

So, are you ready to put your EMF and Torque knowledge to the test? Let's get started with our carefully curated MCQs!

EMF and Torque MCQs | Page 1 of 4

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Q1.
In which mode machine is operating, given that conductor current is in the same direction of conductor emf?

a.

Motoring

b.

Generating

c.

Can’t be determined using directions

d.

In both modes for different cycles

Discuss
Answer: (b).Generating
Q2.
Nature of the flux density wave in the air gap is__________ (for armature current equal to 0)

a.

Flat topped with quarter wave symmetry

b.

Point topped with quarter wave symmetry

c.

Flat topped with half wave symmetry

d.

Point topped with half wave symmetry

Discuss
Answer: (a).Flat topped with quarter wave symmetry
Q3.
In a DC machine, average energy stored in the magnetic field remains constant independent of the armature rotation.

a.

True

b.

False

c.

May be True or False

d.

Can't say

Discuss
Answer: (a).True
Q4.
Emf produced by DC machine, for zero armature current (E1) and non-zero armature current (E2) can be related as__________

a.

E1 = E2

b.

E1 > E2

c.

E1 < E2

d.

Can’t be determined

Discuss
Answer: (a).E1 = E2
Q5.
Average coil emf for 20 coil turns (E1) and 40 coil turns (E2), will have ratio E1/E2=____ (assuming all other parameters same for both machines).

a.

1/2

b.

2/1

c.

1/4

d.

4/1

Discuss
Answer: (a).1/2
Q6.
What is the average coil emf generated in a 4-pole DC machine having flux/pole equal to 0.1 wb rotating at 1500 rpm? (No. of coil sides = 100)

a.

19 kV

b.

1.9 kV

c.

190 V

d.

19 V

Discuss
Answer: (a).19 kV
Q7.
Emf and torque produced in a DC machine are proportional to ________ and _________ respectively.

a.

Armature speed and armature emf

b.

Armature emf and armature speed

c.

Armature current and armature emf

d.

Armature speed and armature current

Discuss
Answer: (d).Armature speed and armature current
Q8.
What is the value of Np in an average coil emf equation, for 10 armature conductors with 2 parallel paths?

a.

2

b.

3

c.

2.5

d.

4

Discuss
Answer: (c).2.5
Q9.
What is the torque equation in terms of B, Ic, l, Zr (r= mean air gap radius)?

a.

Bav*Ic*l*Zr

b.

Bav*Ic*l/Zr

c.

Bav*Ic*Zr/l

d.

Can’t be expressed

Discuss
Answer: (a).Bav*Ic*l*Zr
Q10.
What is the value of pole pitch (in SI unit) for mean air gap radius= 0.5 mm and P=4?

a.

0.785* 10⁻⁶

b.

0.785* 10⁻³

c.

0.785* 10⁻²

d.

0.785* 10⁻⁴

Discuss
Answer: (b).0.785* 10⁻³
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