Question

Right hand thumb rule states that :
A. If we hold the current carrying conductor in the right hand such that the thumb points in the direction of the flow of current, then the fingers encircle the wire in the direction opposite of the magnetic field lines.

B. If we hold the current carrying conductor in the right hand such that the thumb points in the direction of the flow of current, then the fingers encircle the wire in the direction of the magnetic field lines.

C. If we hold the current carrying conductor in the right hand such that the thumb points the magnitude of current, then the fingers encircle the wire in the magnitude of the magnetic field lines.

D. If we hold the current carrying conductor in the right hand such that the thumb points in the direction of the magnetic field lines, then the fingers encircle the wire in the direction of the electric current.

Answer 1

Hint: A current carrying conductor produces a magnetic field in its surrounding. Right hand thumb rule is a rule that gives a relation between the directions of the current flowing in a conductor and the magnetic field lines that the current produces.

Complete answer:
A moving charge particle produces an electric current. And an electric current produces magnetic field lines in the surrounding. The material that carries the current is called a conductor. Therefore, we can reframe our statement as a current carrying conductor produces a magnetic field in its surrounding.

There exist many laws and rules, which help us to understand how the current and the magnetic field lines are related. One of those rules is the right thumb rule. It gives us the direction of the magnetic field lines produced by the current carrying conductor.

Consider a straight current carrying conductor for easy understanding.According to the right thumb rule, if we hold the current carrying conductor in our right hand such that the thumb of that hand points in the direction of the current flowing in the conductor, then the direction of the magnetic field lines will be in the direction in which we which our fingers curl or the direction in which our fingers encircle.Now, out of the given four options the option that matches with the above statement is option B.

Hence, the correct option is B.

Note: We know that when the current carrying conductor is placed in an external magnetic field, the external magnetic field exerts a magnetic force on the conductor. The direction of the magnetic force exerted on the conductor is given by Fleming's left hand rule.