# Motor Inertia MCQ [Free PDF] – Objective Question Answer for Motor Inertia Quiz

1. Hooke’s law is applicable within the elastic limit.

A. True
B. False

Hooke’s law is only applicable within the elastic limit. It states that within the elastic limit the strain is directly proportional to the stress.

2. Calculate the load stress if the value of force is 20 N and the area of the cross-section is 2 m2.

A. 10 N/m2
B. 20 N/m2
C. 30 N/m2
D. 40 N/m2

The stress is defined as the ratio of the internal restoring force and the area of the cross-section.

Stress=Fres÷A=20÷2=10 N/m2.

3. What is the effect of impurities on elasticity?

A. It will increase
B. Remains the same
C. It will decrease
D. It will slightly increase

The Young modulus of elasticity is slightly increased by the addition of impurities. The intermolecular forces inside the wire are effectively increased by impurity due to this external force can be easily opposed.

4. Which of the following are the types of Stress?

A. Longitudinal stress, Volume stress, Tangential stress
B. Longitudinal stress, Volume stress
C. Longitudinal stress, Lateral stress, Tangential stress
D. Longitudinal stress, Shear stress

Three types of stress are Longitudinal stress, Volume stress, Tangential, or Shear stress. Stress is the ratio of restoring force and cross-section area.

5. The relationship between Young’s modulus (Y), Bulk modulus (K) and Poisson’s ratio (μ) is _____________

A. Y=K(1-2μ)
B. Y=3K(1-2μ)
C. Y=5K(1-2μ)
D. Y=4K(1-8μ)

The relationship between Young’s modulus (Y), Bulk modulus (K), and Poisson’s ratio (μ) is Y=3K(1-2μ).

The Young modulus of elasticity is defined as the ratio of Longitudinal stress and Longitudinal strain.

6. Calculate the work done in stretching the wire of volume=22 m3 and the values of stress and strain are 2 N/m2 and 4.

A. 66 J
B. 44 J
C. 22 J
D. 88 J

The work done in stretching a wire is .5 × Stress × Strain × Volume.

The value of the work done is

.5 × 22 × 4 × 2=88 J.

7. Plasticity is the ability of the material to deform without breaking.

A. True
B. False

Plasticity is the ability of the material to deform without breaking. Plastic deformation occurs in metal forming processes.

8. _________ motor operates at low power factor.

A. Capacitor run
B. Capacitor start
D. Reluctance

Shaded pole motors operate at a low power factor. There is a weak magnetic field develops in the case of the Shaded pole motor. It is a single-phase AC Induction motor.

9. Calculate the compensator rating required for cos(Φ)=.7.

A. 0.71 P.U
B. 0.21 P.U
C. 0.47 P.U
D. 0.12 P.U

The compensator rating can be calculated using the relation

QP.U=√1-cos2(∅)

=√1-.49=.71.

This per unit value VAR compensator is required to improve the power factor of the system.

10. Full form of SPWM.

A. Sinusoidal pulse width modulation
B. State per width modulation
C. State pulse width modulation
D. Sinusoidal per width modulation