AP EAMCET202017 Sep 2020Morning ShiftPhysicsMagnetic Effects of CurrentActual
A current (I ) a flows in a circular arc of radius (r ) subtending an angle ( ) as shown in the figure. Find the magnetic field at the centre (O ) of the circle.
Options
- A( ₀ I 4 r )
- B( 2 ₀ I 4 r )
- C( 2 ₀ I 2 r )
- D( 2 ₀ I 4 r )
Correct answer
A. ( ₀ I 4 r )
Step-by-step solution
Magnetic field at the centre due to current carrying circular loop is given as (B_C= ₀ I 2 r ) ...(i) Magnetic field due to current carrying circular arc making an angle ( ) at the centre, is given as ( aligned & B= 2 B_C= 2 ₀ I 2 r [From Eq. (i)] & B= ₀ I 4 r aligned )