Question

Magnetic Field due to a horseshoe magnet is parallel to the plane of the paper and the north pole is on the left. Direct current in a straight wire is perpendicular to the plane of the paper, toward the observer. The wire will be deflected
(A). Downward
(B). Upward
(C).On the right
(D). First upward then downward

Answer 1

Hint: Determine the position of wire with respect to the horseshoe. Due to the direction of flow of current, determine the direction of the magnetic field induced by using the right hand thumb rule. To know where the wire will be deflected, determine how the two magnetic fields interact with each other.

Complete answer:
 

A horseshoe magnet is kept near a wire carrying a current. Due to current a magnetic field is induced around the wire whose direction is given by the right hand thumb rule. The right hand thumb rule states that when the right hand is aligned along the wire and thumb points in the direction of flow of current then the motion of fingers give the direction of the magnetic field developed around the wire.
Here, the direction of the magnetic field is anti-clockwise which means that a magnetic north pole is developed.
In magnetism, like poles repel each other and unlike poles attract each other. Therefore, the wire will move away from the north pole of the horseshoe magnet and towards the south pole. So it moves towards the right.
Since it moves towards the right due to magnetic force of attraction.

Therefore, the correct option is (C).

Note:
A dot denotes the direction of current coming out of the paper, towards the observer, while a cross means the direction of current is into the paper away from the observer. When a magnetic field is developed in an anti-clockwise direction in a current carrying wire or loop, a magnetic north pole is formed while; if a magnetic field develops in clockwise direction a south pole is formed.