# Wave Speed Of Standing Wave

1. Oct 5, 2013

### i_ammitija

1. The problem statement, all variables and given/known data

A wire with an alternating current flowing through it is placed in a magnetic field. This causes the wire to oscillate with a frequency equal to the frequency of the current (you will learn about this when we study electromagnetism). The wire has a length (length is measured from the node at which the wire is tied to the pulley) L = 2.46 m. A mass of 244.0 g is hung on the end of the wire. The frequency of the current is initially set to f = 59.8 Hz. Three loops are observed in the wire at this frequency as shown in the diagram.

Image attached with this post!

2. Relevant equations

(2Lf)2= T/µ.

3. The attempt at a solution

µ = T/(2Lf)2 =(0.244*9.8)/(2* 2.46m*59.8 Hz)^2

This answer was wrong according when inserted!

Any help finding the velocity or the mass per unit length is kindly appreciated!
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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2. Oct 5, 2013

### Staff: Mentor

What does the second "2" mean?

Where did you calculate the wave-length of the oscillation (or, equivalently, where did you use the information that there are three loops)?

3. Oct 5, 2013

### i_ammitija

I wasn't too sure how to incorporate that :/ I'm an economics student, doing this physics subject as an elective. I wasn't too sure how you could relate the three looops.

4. Oct 6, 2013

### Staff: Mentor

Imagine how the loop looks at some specific point in time. A bit like this: "^u^". How many wavelengths are this? And the next question, what is the wavelength then?