AP EAMCET202119 Aug 2021Evening ShiftPhysicsMagnetic Effects of CurrentActual
The magnetic field, of a given length of wire for single turn coil, at its center is ' B ' . then its value for two turns coil for the same wire is
Options
- AB 4
- BB 2
- C4 B
- D2 B
Correct answer
C. 4 B
Step-by-step solution
Magnetic field, B = μ n i a After turning the coils into 2 turns, n ' = 2 n ,   a ' = a 2 ⇒ B ∝ n a ⇒ B ' B = n ' n × a a ' ⇒ B ' B = 2 n n × 2 a a ⇒ B ' B = 4 ⇒ B ' = 4 B