A constant voltage of \( 50\text{ V} \) is maintained between the points A and B of the circuit shown in the figure. The current through the branch CD of the circuit is :

The bridge is a balanced Wheatstone bridge since \( \frac{R_{AC}}{R_{AD}} = \frac{1}{3} \) and \( \frac{R_{CB}}{R_{DB}} = \frac{2}{4} = \frac{1}{2} \). Wait, \( \frac{1}{3} \neq \frac{2}{4} \). Let us re-verify: resistances are \( 1\,\Omega \), \( 2\,\Omega \), \( 3\,\Omega \), \( 4\,\Omega \). Equivalent resistance \( R_{eq} = \frac{(1+2)(3+4)}{(1+2)+(3+4)} = \frac{3 \times 7}{3+7} = \frac{21}{10} = 2.1\,\Omega \). Total current \( I = 50 / 2.1\dots \) Let's use nodal analysis: potentials at C and D.