\(H_2\) = Magnetic field at \(M\) due to \(QR\) + magnetic field at \(M\) due to \(QS\) + magnetic field at \(M\) due to \(PQ\)
\( = 0 + \frac{{{H_1}}}{2} + {H_1} = \frac{3}{2}{H_1}\)
\(==>\)\(\frac{{{H_1}}}{{{H_2}}} = \frac{2}{3}\)
(ઇલેક્ટ્રૉનનો વિજભાર $=1.6 \times 10^{-19}\,C$)