KCET2008PhysicsMagnetic Effects of Current
Current I is flowing in conductor shaped as shown in the figure. The radius of the curved part is r and the length of straight portion is very large. The value of the magnetic field at the centre O will be
Options
- A₀ I 4 r ( 3 2 +1 )
- B₀ I 4 r ( 3 2 -1 )
- C₀ I 4 r ( 2 +1 )
- D₀ I 4 r ( 2 -1 )
Correct answer
A. ₀ I 4 r ( 3 2 +1 )
Step-by-step solution
B _ A =0 aligned B _ B &= ₀ 4 (2 &= ₀ 4 3 I 2 r B _ C &= ₀ I 4 r aligned So, net magnetic field at the centre aligned &= B _ A + B _ B + B _ C &=0+ ₀ 4 3 I 2 r + ₀ I 4 r = ₀ 4 I r ( 3 2 +1 ) aligned