NEET2007PhysicsMagnetic Effects of CurrentActual
What is the magnetic field at a distance (R ) from a coil of radius (r ) carrying current (I ) ?
Options
- A( ₀ I R^2 2 (R^2+r^2 )^ 3 2 )
- B( ₀ I r^2 2 (R^2+r^2 )^ 3 2 )
- C( ₀ I 2 r )
- D( ₀ I 2 R )
Correct answer
B. ( ₀ I r^2 2 (R^2+r^2 )^ 3 2 )
Step-by-step solution
A coil of radius (r ) carrying current (I ), magnetic field at a point at a distance (R ) from the centre of the coil is given by (B= ₀ I r^2 2 [R^2+r^2 ]^ 3 / 2 ) At the centre of a coil, (R=0 ) ( B= ₀ I r^2 2 r^3 = ₀ I 2 r )