A violinist places her finger so that the vibrating section of a 1.20 g/m string has a length of 40.0 cm, then she draws her bow across it.

A violinist places her finger so that the vibrating section of a 1.20 g/m string has a length of 40.0 cm, then she draws her bow across it. A listener nearby in a 20 ^circ {rm C} room hears a note with a wavelength of 30.0 cm. What is the tension in this spring?