A cell is connected between the point A and C of a circular conductor ABCD of centre `O, /_AOC = 60^(@)`. If `B_(1_` and `B_(2)` are the magnitude of magnetic fields at O due to the currents in ABC and ADC respectively, the ratio of `B_(1)//B_(2)` is.

Options

A. `0.2`
B. `6`
C. `1`
D. `5`

Answer

C

Explanation

Resistance of ring of angle `300^(@),R_(1)=(5R)/(6)`
Resistance of ring of angle `60^(@), R_(2)=R/6`
`i_(1)=(R_(2))/(R_(1)+R_(2)) i=i/6, i_(2)=i-i/6=(5i)/6`
`B_(1)=(mu_(0)i_(1))/(2a)xx(300^(@))/(360^(@))=(5mu_(0)i)/(72a), ox`
`B_(2)=(mu_(0)i_(2))/(2a)xx(60^(@))/(360^(@))=(5mu_(0)i)/(72a), o.`
`(B_(1))/(B_(2))=1`