Consider the situation shown in figure (38-E17). The wires \( P_{1} Q_{1} \) and \( P_{2} Q_{2} ...

Consider the situation shown in figure (38-E17). The wires \( P_{1} Q_{1} \) and \( P_{2} Q_{2} \) are made to slide on the rails with the same speed \( 5 \mathrm{~cm} \mathrm{~s}^{-1} \). Find the electric current in the \( 19 \Omega \) resistor if (a) both the wires move towards right and (b) if \( P_{1} Q_{1} \) moves towards left but \( P_{2} Q_{2} \) moves towards right.