This set of Basic Electrical Engineering MCQs focuses on “Determination of the B/H Characteristic”.
1. The B/H characteristics can be determined using _______
a) Ammeter
b) Fluxmeter
c) Voltmeter
d) Multimeter
View Answer
Explanation: The fluxmeter is an electronic display instrument used to measure the magnetic flux of permanent magnets hence it can be used to determine B/H characteristics.
2. The B/H curve can be used to determine?
a) Iron loss
b) Hysteresis loss
c) Voltage loss
d) Eddy current loss
View Answer
Explanation: Hysteresis loss is basically a heat loss due to the reversal of magnetisation of the transformer core whenever it is subjected to a changing magnetic field. It can be determined using the B/H curve.
3. The B/H ratio is not constant for ________
a) Diamagnetic materials
b) Ferromagnetic materials
c) Paramagnetic materials
d) Non-magnetic materials
View Answer
Explanation: As the magnetizing field increases, the relative permeability increases, reaches a maximum, and then decreases. Due to varying permeability, B/H ratio is not constant for ferromagnetic materials.
4. When using a fluxmeter, if the flux changes from Φ to -Φ, what happens to the current?
a) Becomes zero
b) Becomes infinity
c) Remains the same
d) Reverses
View Answer
Explanation: When the flux changes from Φ to -Φ, the current direction will change as the direction of flux is changing.
5. Why is the coil of a ballistic galvanometer wound on a non- metallic former?
a) To minimise damping when high resistance is connected in series
b) To maximise damping when high resistance is connected in series
c) To minimise damping when high resistance is connected in parallel
d) To maximise damping when high resistance is connected in parallel
View Answer
Explanation: The coil of ma ballistic galvanometer is wound on a nonmagnetic former in order to minimise damping when high resistance is connected in series.
6. The ballistic galvanometer is usually lightly damped so that ________
a) It can oscillate
b) It will remain stable
c) Amplitude of the first swing is very large
d) Amplitude of the first swing is very small
View Answer
Explanation: The ballistic galvanometer is usually lightly damped so that the amplitude of its first swing is very large.
7. PMMC instruments can be used as a fluxmeters by _______
a) Using a low resistance shunt
b) Removing the control spring
c) Making the control springs having a large moment of inertia
d) Using a high resistance in series
View Answer
Explanation: A PMMC or a permanent moving magnet coil instrument can be used as a fluxmeter by removing the control spring.
8. Hysteresis loss is determined from _______
a) B/H curve
b) H/B curve
c) BH curve
d) B2H curve
View Answer
Explanation: Hysteresis loss is basically a heat loss due to the reversal of magnetisation of the transformer core whenever it is subjected to a changing magnetic field. It can be determined using the B/H curve.
9. What is a PMMC instrument?
a) Permanent moving magnet coil instrument
b) Permanent machine magnet coil instrument
c) Permanent moving machine coil instrument
d) Premature moving magnet coil instrument
View Answer
Explanation: A PMMC instrument is a permanent moving magnet coil instrument. It uses two magnets to create a stationary magnetic field.
10. B/H curve shows the relationship between?
a) Magnetic field strength and magnetic flux
b) Magnetic field strength and magnetic flux density
c) Current and magnetic flux density
d) Voltage and magnetic flux density
View Answer
Explanation: The B/H curve shows the relation between magnetic field strength and magnetic flux density.
Sanfoundry Global Education & Learning Series – Basic Electrical Engineering.
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