MCAT Physical : Induction

Study concepts, example questions & explanations for MCAT Physical

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Example Questions

Example Question #1 : Induction

You look at a circular loop of wire such that the plane of the loop is perpendicular to your line of vision. The loop has a constant current that is running through it clockwise. What will happen if a magnetic field were to be activated that is pointing in your direction?

Possible Answers:

The current in the loop will continue clockwise but will increase

The current in the loop will begin to move counterclockwise but slowly decrease

The current in the loop will begin to move counterclockwise and slowly increase

The current in the loop will continue clockwise but will decrease

The current in the loop will begin to move counterclockwise at the same magnitude of current as before 

Correct answer:

The current in the loop will continue clockwise but will increase

Explanation:

This question works with the concept of induction. Simply put, the current in a wire will adjust such as to oppose a change in magnetic field. The loop originally has a magnetic field pointing away from the observer. Therefore, with the external magnetic field suddenly activated in the opposite direction (towards the observer), the current in the loop will act to counteract this change and increase while remaining clockwise.

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