Class 9 Physics · Chapter 8 · Test 3
Magnetic Applications
51 MCQs
51 questions · 40 min · 51 marks
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Sample questions
The first 5 of 51. Try each one, then tap to see the answer.
Question 1
Which devices are listed in the chapter as using permanent magnets?
- AElectric motors and generators
- BGlass thermometers only
- CWooden rulers only
- DPlastic bottles only
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Answer: A
The chapter identifies permanent magnets as essential parts of electric motors and generators.
Question 2
Which device uses a permanent magnet to help produce sound?
- AMoving-coil loudspeaker
- BCircuit breaker only
- CLiquid-in-glass thermometer
- DMagnetic relay only
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Answer: A
A moving-coil loudspeaker uses a permanent magnetic field interacting with current in its voice coil.
Question 3
Why are magnetic strips fitted to refrigerator doors?
- ATo keep the doors tightly closed
- BTo heat the refrigerator
- CTo measure the food temperature directly
- DTo generate electricity for the refrigerator
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Answer: A
Magnetic strips help refrigerator and freezer doors remain tightly closed.
Question 4
How can magnets help in flourmills?
- ABy removing iron nails from grains
- BBy removing all water from grains
- CBy changing grains into iron
- DBy increasing the size of grain particles magnetically
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Answer: A
Magnets are used to separate iron objects from grain before grinding.
Question 5
Which use of magnets in medicine is mentioned in the chapter?
- ARemoving iron splinters from the eyes
- BMeasuring blood pressure directly
- CProducing all medicines
- DReplacing every surgical instrument
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Answer: A
The chapter notes that a magnet may be used to remove iron splinters from the eyes.
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