A closed loop PQRS carrying a current is placed in a uniform magnetic field. If the magnetic forces on segments PS, SR and RQ are $F_1, F_2$ and $F_3$ respectively and are in the plane of the paper and along the directions shown, the force on the segment QP is

• A

  $F_3-F_1+F_2$
• B

  $F_3-F_1-F_2$
• Correct answer
  C

  $\sqrt{\left(F_3-F_1\right)^2+F_2^2}$
• D

  $\sqrt{\left(F_3-F_1\right)^2-F_2^2}$

Solution

Since net force on current carrying loop in uniform magnetic field is zero therefore force on remaining segment will be equal and oppsoite to $\mathrm{F}$.

Hence, the correct answer is option: 'C'.