Question 1

The .......motors, because of their inherent characteristics, are best suited for the rolling mills
A)dc motors
B)slip ring induction motors
C)squirrel cage induction motors
D)single phase motors.

Accepted Answer

DC motors are best suited for rolling mills due to their excellent speed control and high starting torque capabilities, which are essential for the heavy-duty operations in rolling mills.

Question 2

In case of kiln drives
A)starting torque is almost zero
B)starting torque and running torque are nearly equal
C)starting torque is more than double of the running torque.
D)all of the above

Accepted Answer

Kiln drives require a high starting torque because they need to overcome the inertia of the kiln at startup, which is significantly more than the torque required to keep it rotating once it has reached its operating speed. This makes the starting torque more than double the running torque.

Question 3

Belt conveyors offer
A)zero starting torque
B)low starting torque
C)medium starting torque
D)high starting torque.

Accepted Answer

D

Question 4

In case belt conveyors
A)squirrel cage motors with direct-on-line starters are used
B)single phase induction motors are used
C)dc shunt motors are used
D)induction motors with star-delta starters are used.

Accepted Answer

Squirrel cage motors with direct-on-line starters are commonly used for belt conveyors due to their simplicity, reliability, and ability to handle the high starting torque required.

Question 5

Which of the following motor is preferred for blowers ?
A)wound rotor induction motor
B)squirrel cage induction motor
C)dc shunt motor
D)dc series motor.

Accepted Answer

Squirrel cage induction motors are preferred for blowers due to their rugged construction, low maintenance, and high reliability, especially under variable load conditions.

Question 6

Centrifugal pumps are usually driven by
A)dc shunt motors
B)dc series motors
C)squirrel cage induction motors

Accepted Answer

Centrifugal pumps are typically driven by squirrel cage induction motors due to their rugged construction, reliability, and the ability to run directly from an AC power supply without the need for a DC converter.

Question 7

In case of centrifugal pumps the starting torque is generally
A)double the running torque
B)slightly more than running torque
C)same as running torque
D)less than running torque.

Accepted Answer

Centrifugal pumps typically have a starting torque that is less than the running torque because they do not require high torque to start up, unlike positive displacement pumps.

Question 8

In a centrifugal pump if the liquid to be pumped has density twice that of water, then the horse power required (as compared to that while pumping water) will be
A)half
B)same
C)double
D)four times.

Accepted Answer

The horsepower required for a centrifugal pump is directly proportional to the density of the liquid being pumped. Therefore, if the density of the liquid is twice that of water, the horsepower required would also double.

Question 9

Wound rotor and squirrel-cage motors with high slip which develop maximum torque at stand still are used for
A)machine tools
B)presses and punches
C)elevators
D)all of the above.

Accepted Answer

Presses and punches require high starting torque, which is provided by motors with high slip and maximum torque at standstill.

Question 10

Belted slip ring induction motor is almost invariably used for
A)centrifugal blowers
B)jaw crushers
C)water pumps
D)screw pumps.

Accepted Answer

Belted slip ring induction motors are used for applications requiring high starting torque, such as jaw crushers.

Question 11

A solar cell converts light energy into __________
A)Electrical energy
B)Thermal energy
C)Sound energy
D)Heat energy

Accepted Answer

A solar cell converts light energy directly into electrical energy through the photovoltaic effect.

Question 12

There are three types of the solar cells.
A)True
B)False
C)none
D)all of the above

Accepted Answer

There are three main types of solar cells: monocrystalline, polycrystalline, and thin-film.

Question 13

The output power of the centrifugal pump is proportional to the _________ of the speed.
A)Square
B)Cube
C)Square-root
D)Cube-root

Accepted Answer

The output power of a centrifugal pump is proportional to the cube of its speed. This relationship is a fundamental principle in fluid dynamics, indicating that if the speed of the pump is doubled, the output power increases by a factor of eight (2^3).

Question 14

There are four types of Water pumps.
A)True
B)False
C)none
D)all of the above

Accepted Answer

There are more than four types of water pumps, including submersible pumps, centrifugal pumps, booster pumps, and positive displacement pumps, among others.

Question 15

The output of the Solar panel is DC.
A)True
B)False
C)none
D)all of the above

Accepted Answer

Solar panels generate electricity by converting sunlight into direct current (DC) electricity, hence the statement is true.

Question 16

Which of the relationship is correct in Permanent magnet DC motor?
A)T ? (I(A)2
B)T ? (I(A)0
C)T ? Ia
D)T2 ? Ia

Accepted Answer

The torque (T) in a permanent magnet DC motor is directly proportional to the armature current (Ia), hence the correct relationship is T ? Ia.

Question 17

Which of the relationship is correct in Permanent magnet DC motor?
A)E ? (N)
B)E ? (N).
C)E ? N
D)E2 ? N.

Accepted Answer

In a permanent magnet DC motor, the back electromotive force (EMF) E is directly proportional to the speed N of the motor, represented as E ∝ N.

Question 18

Who made the first solar cell?
A)Gerald Pearson
B)Tim Bell
C)Tim Cook
D)Nicola Tesla

Accepted Answer

Gerald Pearson, along with Calvin Fuller and Daryl Chapin, developed the first practical silicon solar cell in 1954.

Question 19

When was the first solar cell invented?
A)1950
B)1954
C)1965
D)1952

Accepted Answer

The first practical solar cell was invented in 1954 by Bell Labs.

Question 20

Which of the following is an advantage of electric traction over other methods of traction ?
A)Faster acceleration
B)No pollution problems
C)Better braking action
D)All of the above

Accepted Answer

The answer of Which of the following is an advantage...

Quiz 10: Motor and Power Systems

The .......motors, because of their inherent characteristics, are best suited for the rolling mills

In case of kiln drives

Belt conveyors offer

In case belt conveyors

Which of the following motor is preferred for blowers ?

Centrifugal pumps are usually driven by

In case of centrifugal pumps the starting torque is generally

In a centrifugal pump if the liquid to be pumped has density twice that of water, then the horse power required (as compared to that while pumping water) will be

Wound rotor and squirrel-cage motors with high slip which develop maximum torque at stand still are used for

Belted slip ring induction motor is almost invariably used for

A solar cell converts light energy into __________

There are three types of the solar cells.

The output power of the centrifugal pump is proportional to the _________ of the speed.

There are four types of Water pumps.

The output of the Solar panel is DC.

Which of the relationship is correct in Permanent magnet DC motor?

Which of the relationship is correct in Permanent magnet DC motor?

Who made the first solar cell?

When was the first solar cell invented?

Which of the following is an advantage of electric traction over other methods of traction ?