Concepts Of Physics MCQ Edition [Volume 2]
- Exam
- Concepts Of Physics MCQ Edition [Volume 2]
- Subject
- Physics
- Chapter
- Magnetic Field due to a Current
Concepts Of Physics MCQ Edition [Volume 2] · Physics · Magnetic Field due to a Current
As shown in the figure, a square loop PQRS carrying a current of...
As shown in the figure, a square loop carrying a current of is situated near a long wire carrying . Determine the net magnetic force on the square loop.


Options
- A towards right
- B towards right
- C towards right
- D towards left
Correct answer
C. towards right
Step-by-step solution
The magnetic force on a straight wire of length carrying current placed at a distance from a long straight wire carrying current is given by:
The forces on the horizontal segments and are equal and opposite, and their net force is zero.
For the side of the square loop:
The current in is downwards, which is anti-parallel to the current in the long wire. Therefore, the force on is repulsive (towards the right).
Distance
Length
(towards right)
For the side of the square loop:
The current in is upwards, which is parallel to the current in the long wire. Therefore, the force on is attractive (towards the left).
Distance
(towards left)
The net magnetic force on the loop is:
Since , the net force is directed towards the right.
The forces on the horizontal segments and are equal and opposite, and their net force is zero.
For the side of the square loop:
The current in is downwards, which is anti-parallel to the current in the long wire. Therefore, the force on is repulsive (towards the right).
Distance
Length
(towards right)
For the side of the square loop:
The current in is upwards, which is parallel to the current in the long wire. Therefore, the force on is attractive (towards the left).
Distance
(towards left)
The net magnetic force on the loop is:
Since , the net force is directed towards the right.