For induced emf to be produced in a coil, the magnetic flux linked with the coil must:
Correct answer: D. Be Changed
- A. Only decrease
- B. Only increase
- C. Be constant
- D. Be Changed
Explanation
According to Faraday's law of electromagnetic induction, induced emf is generated when there is a change in magnetic flux through a coil. This change can be an increase or decrease in the magnetic flux. Therefore, the correct answer is that the magnetic flux must be changed to induce emf. Options A and B are incorrect because, while they mention changes in flux, they limit the scope to only decreases or increases, respectively, which does not encompass all scenarios of change. Option C is incorrect as it states that the magnetic flux must be constant, which would result in no induced emf. Hence, only a change in magnetic flux (either increase or decrease) can lead to the production of induced emf.
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About Electromagnetism
Magnetic flux density and magnetic flux describe the strength of a magnetic field and the field passing through a surface. A charged particle moving through a magnetic field experiences a force perpendicular to its velocity and may follow circular or helical motion, depending on the angle between velocity and field.
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