According to Fleming's right-hand rule, if the forefinger indicates the direction of magnetic field and thumb shows the direction of motion of conductor, then the stretched middle finger will predict
- A.force acting on the conductor
- B.electric field
- C.induced current
- D.current
Correct answer
Explanation
The correct answer is C, induced current. Fleming's right-hand rule is used for electromagnetic induction, as in a generator, and its middle finger gives the direction of the current induced in the conductor. Stretch the thumb, forefinger and middle finger of the right hand so that they are at right angles to one another. The forefinger points along the magnetic field, the thumb along the motion of the conductor, and the middle finger then shows the direction of the induced current. This rule applies when mechanical motion produces electricity. Its partner, Fleming's left-hand rule, applies to electric motors, where a current-carrying conductor in a magnetic field experiences a force, and there the thumb shows the force or motion. Option A is wrong because finding the force on a conductor is the job of the left-hand rule. Option B is wrong because neither rule gives the direction of an electric field. Option D is wrong because the rule gives specifically the induced current produced by the motion, not just any current flowing in a circuit. Exam tip: right hand = generator (induced current); left hand = motor (force); remember FBI – thumb, fore, middle.
Practice Questions
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- B.Martin Luther
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- D.Copernicus
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