JEE Main202117 Mar 2021Evening ShiftPhysicsMagnetic Effects of CurrentActual
A hairpin like shape as shown in figure is made by bending a long current carrying wire. What is the magnitude of a magnetic field at point P which lies on the centre of the semicircle ?
Options
- Aμ 0 I 4 π r ( 2 - π )
- Bμ 0 I 4 π r ( 2 + π )
- Cμ 0 I 2 π r ( 2 + π )
- Dμ 0 I 2 π r ( 2 - π )
Correct answer
B. μ 0 I 4 π r ( 2 + π )
Step-by-step solution
B = 2 × B st . wire + B loop B = 2 × μ 0 i 4 π r + μ 0 i 2 r π 2 π B = μ 0 i 4 π r ( 2 + π )