The direction of the magnetic field produced around a straight current-carrying conductor is given by
- A.Fleming's left hand rule
- B.the right hand thumb rule
- C.Fleming's right hand rule
- D.Lenz's law
Correct answer
Explanation
The correct answer is B, the right hand thumb rule, also called Maxwell's corkscrew rule. Hold the conductor in your right hand with the thumb stretched along the direction of the conventional current; the way your fingers curl round the wire is the direction of the concentric magnetic field lines. The field is strongest close to the wire and weakens with distance.
Option A, Fleming's left hand rule, gives the direction of the force on a current-carrying conductor placed in a magnetic field, which is the principle of the electric motor, not the shape of the field around a wire. Option C, Fleming's right hand rule, gives the direction of the current induced in a conductor moved in a magnetic field, the principle of the generator. Option D, Lenz's law, states that the induced current opposes the change that produced it, which again concerns induction. Only the right hand thumb rule answers the question asked.
Read the full article: Electricity and Magnetism: Laws, Rules and PYQs
Practice Questions
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