Calculating Length of Stretched Wire from Frequency

[Travian]

Homework Statement

The second harmonic frequency on a stretched wire, with a tension of 50 N and a mass per unit length density of 0.025 kg m-1, is measured to be 200 Hz. What is the length of the wire?

Homework Equations

L=λ/2

The Attempt at a Solution

As far as I've discovered i must find L, but i am not sure if this is the correct formula:
L=λ/2

In case it is correct, then what is the relation between mass, frequency,tension and length.

If it is not, then what formula i should use in order to get length?

I searched throughout google, but i couldn't find any other formulas. Totally confused:/

 

[Travian]

someone?

 

[novop]

Hi. The velocity of the propagating wave $$v=\sqrt{\frac{T}{u}}$$ where $${u}$$ is the mass per unit length.

In the second harmonic frequency, $$\lambda = L$$.

Use $$v=\lambda{f}$$ to solve the rest.