I put this in the intro forum about 3-4 hours ago and no one answered, can anyone here help?(adsbygoogle = window.adsbygoogle || []).push({});

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

An experiment on the Earth's magnetic field is being carried out 1.00m from an electric cable. What is the maximum allowable current in the cable if the experiment is to be accurate to +/- 1.0%

2. Relevant equations

B= uI/2(pi)r

B is proportional to I/R where B is the magnetic field and pi=3.14

F=IBI where this is I one and I two.

3. The attempt at a solution

I'm not really sure to do with out any numbers. Is there a way to find B so you can then use the first formula I listed to find I using R=1m.

Is there a way to express B in terms of that percentage? The answer is 2.5A

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# Homework Help: Magnetic Fields and Current experiment

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