When a light wave is incident at the interface between two media, the reflection coefficient is given by $$\frac{(n - 1)^2}{(n + 1)^2}$$ where $$n$$ is the refractive index of the denser medium with respect to the rarer medium. Two stretched strings whose linear densities are 25 g/m and 9 g/m are joined together. Assuming the law of optics holds good here also, the reflection coefficient for the pulse along the strings is