Physics problems driving me crazy- each book has different formulas

AI Thread Summary
The discussion centers on calculating the electric potential difference (delta V) between two parallel metal plates separated by 3.0 mm with an electric field of 250 V/m. The equation used is E = - delta V / delta D, leading to confusion about the sign of the result. The correct interpretation is that while the electric field points to the lower potential, the distance (D) is always considered positive. Therefore, the absolute value of delta V should be taken, resulting in a positive 0.75 V. The clarification emphasizes the importance of understanding directionality in electric fields and potential differences.
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Homework Statement


The electric potential difference between two parallel metal plates is delta V. The plates are separated by a distance of 3 .0 mm and the electric field between the plats is E = 250 V / m. Calculate delta V


Homework Equations



E = - delta V / delta D

The Attempt at a Solution



250 V / m = - 120 V / D

D = -0.75 V

The answer says 0.75 V.

Is it positive or negative? can someone help?

The prior question I solved, using this formula and plugging in values gave me -1.2 * 10^3 N/C.

So, why is it positive? Thanks
 
Physics news on Phys.org
"Electric field between the plates" does not specify the direction of the field. It points to the lower potential. Calculate with the absolute values. A distance is always positive.

ehild
 

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