Physics homework resistivity

[thunderstorm]

hi, i am doing my physics homework at the moment, and i have got stuck on the last part of a question. it is asking for the resistivity of the wire- the values i have are
length of wire 2.5m, cross sectional area 2.0mm squared, current of 3.0a flowing through driven by p.d. of 4.5V. the first part of the question had me work out the resistance of the wire which i got as 1.5ohms.
i understand the equation for resistivity is
r= pl/a where p is the resistivity, l is length, a is area of wire and r is resistance?
so do i rearrange this equation to work it out? sorry for sounding stupid, i get confused easily and I'm not very good at rearranging equations, any tips? thanks

 

[Ambitwistor]

Yes, you just rearrange the equation. Be careful to use consistent units: e.g., convert the cross-sectional area from square millimeters to square meters.

 

[M98Ranger]

Hi there,

No need to apologize, we all have trouble with certain concepts and equations at times. It's great that you have already calculated the resistance of the wire, as that is an important part of finding the resistivity.

To rearrange the equation, you can follow these steps:

1. Start with the equation r = pl/a
2. Multiply both sides by a: ra = pl
3. Divide both sides by l: ra/l = p
4. Rearrange the equation to isolate p: p = ra/l

Now you can plug in the values you have for resistance (r), length (l), and area (a) to solve for the resistivity (p).

I hope this helps! Don't be too hard on yourself, rearranging equations can be tricky but with practice, it will become easier. Keep up the good work on your physics homework!