Help hw question driving me crazy

[soconfused]

help... urgent homework question driving me crazy!

Hi. I don't understand this homework question... and I mean I know that I have to use the absolute error and relative error for it, but I don't understand how to find the electric field with the potential difference and distance... I've been looking at it for a while now, and it's due in an hour. This is driving me nuts! Can anyone please help?

You measure 2 potentials and estimate their errors, (1.1+-0.028)V and 0.4V with the same error. You determine the potential difference between these voltages. With the measured distance of (5.543+-0.245)cm between the points where the voltages were measured and the potential difference you calculate the electric field in the region between the 2 points. What is the absolute error of the electric field (hint: calculate the absolute error of the voltage difference, convert it and the absolute error of the distance given to relative errors, calculate the relative error of the electric field, and then convert that to an absolute error.

I'm trying to follow the hint step-by-step, but do I have to double the error of the potentials? I don't know... I'm lost.

 

[soconfused]

one more thing

If it helps, a similar problem, just with different numbers, but with the correct answer, is below.

You measure 2 potentials and estimate their errors, (1.1+-0.022)V and 0.4V with the same error. You determine the potential difference between these voltages. With the measured distance of (4.895+-0.212)cm between the points where the voltages were measured and the potential difference you calculate the electric field in the region between the 2 points. What is the absolute error of the electric field ?

ans: .8874515

 

[kyle8921]

Hi there. It sounds like you're working on a problem involving the electric field and potential difference. I understand that this can be a challenging concept to grasp, but I'm here to help guide you through it.

First, let's review the definitions of absolute error and relative error. Absolute error is the difference between the measured value and the true value, while relative error is the absolute error divided by the true value. In this case, the true value would be the actual electric field.

To find the absolute error of the electric field, we need to first calculate the absolute error of the potential difference and the distance. The absolute error of the potential difference can be found by adding the absolute errors of the two potentials together. So in this case, it would be 0.028V + 0.028V = 0.056V.

Next, we need to convert this absolute error to a relative error. To do this, we divide the absolute error by the true value, which is the potential difference of 0.7V. So the relative error of the potential difference would be 0.056V/0.7V = 0.08.

We follow the same steps for the distance, using the given absolute error of 0.245cm and the true value of 5.543cm. This gives us a relative error of 0.044.

Now, to calculate the relative error of the electric field, we use the formula: relative error = (relative error of potential difference + relative error of distance)/2. So in this case, it would be (0.08 + 0.044)/2 = 0.062.

Finally, to convert this relative error back to an absolute error, we multiply it by the true value of the electric field. So the absolute error of the electric field would be 0.062 * (|E|) = 0.062 * (|E|).

I hope this helps guide you in the right direction. Remember, when in doubt, it's always helpful to review the definitions and formulas involved in the problem. Good luck!