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 3 of 4

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Q21.
Condition for linear magnetization is______

a.

φ α If

b.

φ α Ia

c.

φ α 1/If

d.

φ α 1/Ia

Discuss
Answer: (a).φ α If
Q22.
A 4-pole Dc wound machine is lap wound with 400 conductors. The pole shore is 20 cm long and average flux density over one-pole pitch is 0.4 T, the armature diameter being 30 cm. Here, motor is drawing 25 A current at 1500 rpm.

What is the available torque (N-m) at shaft?

a.

29.9

b.

59.8

c.

14.95

d.

44.85

Discuss
Answer: (a).29.9
Q23.
When Ea>Vt machine is said to be operating in which of the following mode?

a.

Depends on the Shaft speed

b.

Generating

c.

Motoring

d.

Inducing

Discuss
Answer: (b).Generating
Q24.
When Ea<Vt machine is said to be operating in which of the following mode?

a.

Depends on the Shaft speed

b.

Generating

c.

Motoring

d.

Inducing

Discuss
Answer: (c).Motoring
Q25.
Simple equation of DC machine operating in generating mode, with non-zero Ra value is________

a.

Vt = Ea – Ia/Ra

b.

Vt = Ea + Ia*Ra

c.

Vt = – Ea + Ia*Ra

d.

Vt = Ea – Ia*Ra

Discuss
Answer: (d).Vt = Ea – Ia*Ra
Q26.
Simple equation of DC machine operating in motoring mode, with non-zero Ra value is________

a.

Vt = Ea – Ia/Ra

b.

Vt = Ea + Ia*Ra

c.

Vt = – Ea + Ia*Ra

d.

Vt = Ea – Ia*Ra

Discuss
Answer: (b).Vt = Ea + Ia*Ra
Q27.
When torque of the electromagnetic origin is in the opposite direction of rotation of armature, machine is said to be operating in which of the following mode?

a.

Depends on other parameters

b.

Generating

c.

Motoring

d.

Inducing

Discuss
Answer: (b).Generating
Q28.
When torque of the electromagnetic origin is in the direction of rotation of armature, machine is said to be operating in which of the following mode?

a.

Depends on other parameters

b.

Generating

c.

Motoring

d.

Inducing

Discuss
Answer: (c).Motoring
Q29.
What is the armature current for a DC motor if terminal voltage is 255 V and open circuit voltage is equal to 250 V, where armature resistance is 0.05 Ω?

a.

10 A

b.

100 A

c.

1 KA

d.

1 A

Discuss
Answer: (b).100 A
Q30.
For a DC generator feeding 100 kW power into 230 V mains, having armature resistance and field resistance equal to 0.08 Ω and 115 Ω resp. The value of armature current is_____

a.

436.8 A

b.

434.8 A

c.

432.8 A

d.

Data insufficient

Discuss
Answer: (a).436.8 A
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