Question

An infinitely long conductor ` PQR` is bent to form a light angle as shown in Figure . A current `I` flows through `PQR` . The magnetic field due to this current at the point `M` is `H_(1)`. Now , another infinitely long straight conductor `QS` is connected at `Q` so that current is `(I)/(2)` in `QR` as well as in `QS` , the current in `PQ` remaining unchanged . The magnetic field at `M` is now `H_(2)`. The ratio `(H_(1))/(H_(2)` is given by

A. `1//2`
B. `1`
C. `2//3`
D. `2`

Answer 1

Correct Answer - (C)
(iii) `H_(1) = (mu_(0))/(4pi) (I)/(d)`
`H_(2) = (mu_(0)/(4pi)) (I)/(d) + (mu_(0))/(4pi) (I//2)/(d)`
`H_(2) = (3)/(2) (mu_(0))/(4pi) (I)/(d)`
`(H_(1))/(H_(2)) = (2)/(3)`