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

Options

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

Answer

C

Explanation

Magnetic field at any point lying on the current carrying straight conductor is zero. Here `H_(1)` =Magnetic field at `M` due to current in `PQ`
`H_(2)` =Magnetic field at `M` due to `QR` +magnetic field at `M` due to `QS` +magnetic field `M` due to `PQ`
`=0+(H_(1))/2+H_(1)=3/2H_(1) implies (H_(1))/(H_(2))=2/3`