AP EAMCET2004PhysicsMagnetic Effects of Current
A wire of length l is bent into a circular coil of one turn of radius R₁ . Another wire of the same material and same area of cross-section and same lengths is bent into a circular coil of two turns of radius R₂ . When the same current flows, through the two coils, the ratio of magnetic induction at the centres of the two coils is
Options
- A1: 2
- B1:1
- C1:4
- D3:1
Correct answer
C. 1:4
Step-by-step solution
Magnetic induction at the centre of a circular coil array rlrl & B = ₀ 2 n i R B n R Here, & n =1, n₂=2, & l =2 R₁=2 2 R₂ & R₂ = R₁ 2 & B₁ B₂ = n₁ n₂ R₂ R₁ & = 1 2 R₁ / 2 r = 1 4 & B₁: B₂ =1: 4 array