JIPMER2015PhysicsMagnetic Effects of Current
The parts of two concentric circular arcs joined by two radial lines and carries current i . The arcs subtend an angle at the centre of the circle. The magnetic field at the centre O , is
Options
- A₀ i(b-a) 4 a b
- B₀ i(b-a) ( - )
- C₀ i(b-a) a b
- D₀ i(a-b) 2 a b
Correct answer
A. ₀ i(b-a) 4 a b
Step-by-step solution
The field at the centre of a circular loop is given by B= ₀ i 2 a The field due to circular arc of inner circle is B₁= ( 2 ) ₀ i 2 a The field due to circular arc of outer circle is aligned B₂ & = ( 2 ) ( ₀ i 2 b ) B & =B₁-B₂= ₀ i(b-a) 4 a b aligned