Discussion
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- Question
What is the flux density of a magnetic field whose flux is 3000 µWb and cross-sectional area is 0.25 m2?
Options- A. 12,000 µT
- B. 83,330 T
- C. 0 T
- D. More information is needed in order to find flux density.
- Correct Answer
- 12,000 µT
- 1. What is the reluctance of a material that has a length of 0.045 m, a cross-sectional area of 0.015 m2, and a permeability of 2500 µWb/At·m?
Options- A. 833.33 µAt/Wb
- B. 0.27 At/Wb
- C. 1200 At/Wb
- D. More information is needed in order to find the reluctance. Discuss
- 2. A Hall effect sensor
Options- A. exists only in theory
- B. is a noncontacting magnetic sensor
- C. can operate only a few times before failure
- D. produces very large voltages Discuss
- 3. The component that produces power in an electromagnetic generator is called the
Options- A. armature
- B. field winding
- C. commutator
- D. brush Discuss
- 4. The unit for frequency is the
Options- A. hertz
- B. ampere
- C. watt
- D. second Discuss
- 5. Add 21 mA and 8000 µA and express the result in milliamperes.
Options- A. 21.8 mA
- B. 218 mA
- C. 29 mA
- D. 290 mA Discuss
- 6. Which electromagnetic device uses brushes and a commutator?
Options- A. A speaker
- B. A dc generator
- C. A relay
- D. A solenoid Discuss
- 7. The Hall effect
Options- A. is a phenomenon with no practical applications
- B. is used in various sensor applications
- C. can develop potentials of thousands of volts
- D. is the basis for solar cell operation Discuss
- 8. What are the effects of moving a closed wire loop through a magnetic field?
Options- A. A voltage is induced in the wire.
- B. A current is induced in the wire.
- C. The polarity across the wire depends on the direction of motion.
- D. All of the above Discuss
- 9. Which electromagnetic device has a movable iron core called a plunger?
Options- A. A speaker
- B. A dc generator
- C. A relay
- D. A solenoid Discuss
- 10. Which electromagnetic device has a flexible cone?
Options- A. A speaker
- B. A dc generator
- C. A relay
- D. A solenoid Discuss
Magnetism and Electromagnetism problems
Search Results
Correct Answer: 1200 At/Wb
Correct Answer: is a noncontacting magnetic sensor
Correct Answer: armature
Correct Answer: hertz
Correct Answer: 29 mA
Correct Answer: A dc generator
Correct Answer: is used in various sensor applications
Correct Answer: All of the above
Correct Answer: A solenoid
Correct Answer: A speaker
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