what is the net force on the rectangular coil

The net force on a rectangular current-carrying coil placed in a uniform magnetic field is:

0

Explanation

When electric current flows through a rectangular coil inside a uniform magnetic field, forces act on all four sides of the coil.

• The forces on opposite sides are:

  • Equal in magnitude

  • Opposite in direction

Because of this, the forces cancel each other.

Important point

Although the net force becomes zero, the coil may still rotate because a torque acts on it.

Formula for torque on the coil

Torque = N × B × I × A × sinθ

Where:

• N = number of turns

• B = magnetic field strength

• I = current

• A = area of the coil

• θ = angle between magnetic field and normal to the coil

Conclusion

So, in a uniform magnetic field:

• Net force on the rectangular coil = 0

• But the coil can still rotate due to torque.