Two wires $W_1$ and $W_2$ have the same radius r and respective densities $ρ_1$ and $ρ_2$ such that $ρ_2=4ρ_1$. They are joined together at the point $O$, as shown in the figure. The combination is used as a sonometer wire and kept under tension $T$. The point $O$ is midway between the two bridges. When a stationary wave is set up in the composite wire, the joint is found to be a node. The ratio of the number of antinodes formed in $W_1$ to $W_2$ is :

Question

$\begin{array}{1 1}(1) 1 : 1\\ (2) 1 : 2\\ (3) 1 : 3\\ (4) 4 : 1 \end{array}$