JEE Main202228 Jul 2022Evening ShiftPhysicsMagnetic Effects of CurrentActual
The magnetic field at the center of current carrying circular loop is B 1 . The magnetic field at a distance of 3 times radius of the given circular loop from the center on its axis is B 2 . The value of B 1 B 2 will be
Options
- A9 : 4
- B12 : 5
- C8 : 1
- D5 : 3
Correct answer
C. 8 : 1
Step-by-step solution
Magnetic field at the centre of the loop i.e. B 1 = μ 0 i 2 R Magnetic field on the axis of the loop is, B 2 = μ 0 i R 2 2 R 2 + x 2 3 2 = μ 0 i × R 2 2 R 2 + 3 R 2 3 2 = μ 0 i × R 2 2 × 8 R 3 = μ 0 i 2 × 8 R Therefore, the ratio B 1 B 2 = 8 1