Figure shows a meter bridge. Wire \(A C\) has uniform crosssection. The length of wire \(A C\) i....

Figure shows a meter bridge. Wire \(A C\) has uniform crosssection. The length of wire \(A C\) is \(100 cm . X\) is a standard resistor of \(4 \Omega\) and \(Y\) is a coil. When \(Y\) is immersed in melting ice the null point is at \(40 cm\) from point \(A\). When the coil \(Y\) is heated to \(100^{\circ} C\), a \(78 \Omega\) resistor has to be connected in parallel with \(Y\) in order to keep the bridge balanced at the same point.