Question

A straight current carrying conductor is held in exactly vertical direction. In order to produce a clockwise magnetic field around the conductor, the current should be passed in the conductor :
A. from top towards bottom
B. from left towards right
C. from bottom towards top
D. from right towards left

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:
Moving charges or current show magnetic properties. When a current flows through a conducting material, it produces electric field lines around it.It is given that a straight current carrying conductor is placed vertically. As discussed, the current will produce magnetic field lines around the conductor. However, for a particular direction of current, the magnetic field line has a particular direction.

There are many laws and rules, which help us to understand how the current and the magnetic field lines are related (their directions). 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.

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.

It is given that the direction of the magnetic field lines is clockwise. Therefore, if we curl the fingers of the right hand in a clockwise direction the thumb will point downwards. This means that the direction of the current is pointing downwards.

Therefore, in order to produce a clockwise magnetic field around the conductor, the current should be passed in the conductor from top towards bottom.

Hence, the correct option is A.

Note: 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.