Magnetism and Electromagnetism problems
- 1. What do you call the characteristic of a magnetic material whereby a change in magnetization lags the application of a magnetizing force?
Options- A. Hysteresis
- B. Induction
- C. Retentivity
- D. Reluctance Discuss
Correct Answer: Hysteresis
- 2. The unit of flux density is known as
Options- A. magnetomotive force
- B. a weber
- C. a maxwell
- D. a tesla Discuss
Correct Answer: a tesla
- 3. Which two values are plotted on a B-H curve graph?
Options- A. Reluctance and flux density
- B. Permeability and reluctance
- C. Magnetizing force and permeability
- D. Flux density and magnetizing force Discuss
Correct Answer: Flux density and magnetizing force
- 4. "Series" and "parallel" as applied to dc motors refer to
Options- A. the connection of the motor and controller
- B. the connection of the field coil and armature windings
- C. the connection of the brush and commutator
- D. the connection of the motor batteries Discuss
Correct Answer: the connection of the field coil and armature windings
- 5. Which electromagnetic device contains an armature?
Options- A. A speaker
- B. A dc generator
- C. A relay
- D. A solenoid Discuss
Correct Answer: A dc generator
- 6. How much flux is there in a magnetic field when its flux density is 5000 µT and its cross-sectional area is 300 mm2?
Options- A. 16.67 mWb
- B. 5.0 µWb
- C. 3.0 mWb
- D. 1.5 µWb Discuss
Correct Answer: 1.5 µWb
- 7. The polarity of induced voltage while a field is collapsing is
Options- A. independent of the force creating the field
- B. opposite to the force creating the field
- C. identical to the force creating the field
- D. present only if the force is stationary Discuss
Correct Answer: opposite to the force creating the field
- 8. Permeability is the inverse equivalent of which electrical term?
Options- A. Voltage
- B. Current
- C. Resistance
- D. Conductance Discuss
Correct Answer: Resistance
- 9. The ability of a material to maintain a magnetized state (without the presence of a magnetizing force) is called hysteresis.
Options- A. True
- B. False Discuss
Correct Answer: False
- 10. The unit of magnetic flux is the weber.
Options- A. True
- B. False Discuss
Correct Answer: True
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