BITSAT2024PhysicsMagnetic Effects of CurrentActual
A long straight wire of radius a carries a steady current 1 . The current is uniformly distributed across its cross section. The ratio of the magnetic field at a 2 and 2a from axis of the wire is:
Options
- A1: 4
- B4: 1
- C1: 1
- D3: 4
Correct answer
C. 1: 1
Step-by-step solution
Magnetic field due to straight wire, B= ₀ I 2 r Magnetic field at a 2 is, B _ a / 2 = ₀ I 2 ( a / 2) B _ a / 2 ~B _ 2 a = 1 1 =1: 1