Magnetic Measurements MCQs - Electrical and Electronic Measurements

This Portion of Electrical andElectronic Measurements and Measuring instruments contains Magnetic Measurements MCQs (Multiple Choice Questions and Answers) / Objective Type Questions and Answers.

This Section covers below lists of topics.

Types of Tests
Ballistic Tests
Permeameters
Measurement of Leakage Factor with Flux Meter
Alternating Current Magnetic Testing
Methods of measurement of Iron Losses
Methods of measurement of Air Gap Flux
Testing of Permanent Magnets

PRACTICE IT NOW TO SHARPEN YOUR CONCEPT AND KNOWLEDGE

1. Which of the following measures the magnetic flux density?

Ballistic galvanometer
Grassot fluxmeter
Permeameter
All of the above

2. When a magnetic material is subjected to alternating field, loss of power occurs owing to

hysteresis only
eddy current only
both hysteresis and eddy currents
none of the above

3. The area of the hysteresis loop in magnetic specimen indicates

hysteresis and eddy current loss
hysteresis loss
hysteresis loss per unit volume
hysteresis loss per unit volume per cycle of frequency

4. The ratio of total flux to the useful flux in a magnetic circuit is called

form factor
leakage factor
utility factor
dispersion factor

5. Maxwell’s bridge method is used to measure

iron loss and permeability
copper loss
copper loss and iron loss
none of these

6. Ballistic tests are used in magnetic measurements for :

Determination of B-H curve of the specimen only
Determination of hysteresis loop of the specimen only
Determination of flux density, magnetizing force and B-H curve and hysteresis loop of the specimen
Finding out iron losses in the specimen.

7. The true value of flux density in a ring specimen is ____________ Where B’ = measured value of the flux density, H = magnetizing force. A_s = area of cross section of specimen A_c = area of cross section of coil producing magnetizing force.

B = B’ + µ₀H(A_c/A_s -1)
B = B’ - µ₀H(A_c/A_s -1)
B = B’ + µ₀H(A_s/A_c -1)
B = B’ - µ₀H(A_s/A_c -1)

8. The reason for using ring type specimens for ballistic tests is :

They are free from end effects
They require less labour to prepare as compared with bar type specimens
They can be used for large quantities of materials of very small permeability
All the above.

9. Burrow’s permeameter is preffered to other permeameters as it :

Incorporate arrangement for uniform distribution of mmf over the entire length of the specimen
Incorporate arrangement for elimination of leakage flux at the joints
Is very accurate and can serve as reference standard
All the above.

10. In an Epstein square, used for finding the iron loss in a stack of laminations, the laminations are so arranged that

Plane of each lamination is perpendicular to the plane of the square
Plane of each lamination is parallel to the plane of square
The plane of laminations may be either parallel or perpendicular to the plane of the square
The plane of laminations may be at any angle to the plane of square.

11. In a Lloyd Fisher square used for determination of iron loss in a specimen of iron laminations, the current coil of the wattmeter is connected in the primary winding circuit, while the pressure coil is connected in the secondary winding circuit. This is done so that :

The I²R losses in the current coil are not included in the wattmeter reading
The I²R losses in the pressure coil circuit are not included in the wattmeter reading
The I²R losses both in current coil and pressure coil circuit are not included in the wattmeter reading
The wattmeter reads only the iron losses in the specimen of laminations.

12. Iron losses in a specimen of iron are determined by using co-ordinate type of potentiometer. The loss component of no load current is ready by :

Inphase potentiometer
Quadrature potentiometer
Either by inphase or Quadrature potentiometer.
None of the above.

13. The iron loss when measured in the specimen of laminations at a constant maximum flux density of 1.3 Wb/m² are : 20W at 40 Hz and 40 W a 60 Hz. What are the hysteresis and eddy current losses at 50Hz and a flux density of 1.3 Wb/m² ?

10W, 20 W
7.38W, 212.8 W
8.38W, 20.8W
5W,25W

14. Magnetizing force is measured by nuclear magnetic resonance method. The expression for magnetizing force is_________ Where f = frequency in Hz, h = planck’s constant and v_p = gyrometric ratio.

H = f / v_p
H = 2πf / h
H = fh / 4π
H = 2πf / v_p

15. Permanent magnets are tested by :

Ballistic methods
Using an electric circuit having a mutual inductance
Potentiometric methods
Betteridge apparatus.

EXAMRADAR

For Solo Learner Computer science

Electrical and Electronic Measurements – Magnetic Measurements MCQs

1. Which of the following measures the magnetic flux density?

2. When a magnetic material is subjected to alternating field, loss of power occurs owing to

3. The area of the hysteresis loop in magnetic specimen indicates

4. The ratio of total flux to the useful flux in a magnetic circuit is called

5. Maxwell’s bridge method is used to measure

6. Ballistic tests are used in magnetic measurements for :

7. The true value of flux density in a ring specimen is ____________ Where B’ = measured value of the flux density, H = magnetizing force. A_s = area of cross section of specimen A_c = area of cross section of coil producing magnetizing force.

8. The reason for using ring type specimens for ballistic tests is :

9. Burrow’s permeameter is preffered to other permeameters as it :

10. In an Epstein square, used for finding the iron loss in a stack of laminations, the laminations are so arranged that

11. In a Lloyd Fisher square used for determination of iron loss in a specimen of iron laminations, the current coil of the wattmeter is connected in the primary winding circuit, while the pressure coil is connected in the secondary winding circuit. This is done so that :

12. Iron losses in a specimen of iron are determined by using co-ordinate type of potentiometer. The loss component of no load current is ready by :

13. The iron loss when measured in the specimen of laminations at a constant maximum flux density of 1.3 Wb/m² are : 20W at 40 Hz and 40 W a 60 Hz. What are the hysteresis and eddy current losses at 50Hz and a flux density of 1.3 Wb/m² ?

14. Magnetizing force is measured by nuclear magnetic resonance method. The expression for magnetizing force is_________ Where f = frequency in Hz, h = planck’s constant and v_p = gyrometric ratio.

15. Permanent magnets are tested by :

Electrical and Electronic Measurements – Magnetic Measurements MCQs

1. Which of the following measures the magnetic flux density?

2. When a magnetic material is subjected to alternating field, loss of power occurs owing to

3. The area of the hysteresis loop in magnetic specimen indicates

4. The ratio of total flux to the useful flux in a magnetic circuit is called

5. Maxwell’s bridge method is used to measure

6. Ballistic tests are used in magnetic measurements for :

7. The true value of flux density in a ring specimen is ____________ Where B’ = measured value of the flux density, H = magnetizing force. As = area of cross section of specimen Ac = area of cross section of coil producing magnetizing force.

8. The reason for using ring type specimens for ballistic tests is :

9. Burrow’s permeameter is preffered to other permeameters as it :

10. In an Epstein square, used for finding the iron loss in a stack of laminations, the laminations are so arranged that

11. In a Lloyd Fisher square used for determination of iron loss in a specimen of iron laminations, the current coil of the wattmeter is connected in the primary winding circuit, while the pressure coil is connected in the secondary winding circuit. This is done so that :

12. Iron losses in a specimen of iron are determined by using co-ordinate type of potentiometer. The loss component of no load current is ready by :

13. The iron loss when measured in the specimen of laminations at a constant maximum flux density of 1.3 Wb/m2 are : 20W at 40 Hz and 40 W a 60 Hz. What are the hysteresis and eddy current losses at 50Hz and a flux density of 1.3 Wb/m2 ?

14. Magnetizing force is measured by nuclear magnetic resonance method. The expression for magnetizing force is_________ Where f = frequency in Hz, h = planck’s constant and vp = gyrometric ratio.

15. Permanent magnets are tested by :

7. The true value of flux density in a ring specimen is ____________ Where B’ = measured value of the flux density, H = magnetizing force. A_s = area of cross section of specimen A_c = area of cross section of coil producing magnetizing force.

13. The iron loss when measured in the specimen of laminations at a constant maximum flux density of 1.3 Wb/m² are : 20W at 40 Hz and 40 W a 60 Hz. What are the hysteresis and eddy current losses at 50Hz and a flux density of 1.3 Wb/m² ?

14. Magnetizing force is measured by nuclear magnetic resonance method. The expression for magnetizing force is_________ Where f = frequency in Hz, h = planck’s constant and v_p = gyrometric ratio.