Physics problems driving me crazy- each book has different formulas

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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 (E) of 250 V/m. The formula used is E = - delta V / delta D, leading to a calculation of D = -0.75 V. The confusion arises regarding the sign of delta V, with the correct interpretation being that potential differences are expressed as positive values, as distances are always positive and the electric field direction indicates lower potential.

PREREQUISITES
  • Understanding of electric fields and potential differences
  • Familiarity with the formula E = - delta V / delta D
  • Basic knowledge of units in electromagnetism (V, m, N/C)
  • Concept of absolute values in physics calculations
NEXT STEPS
  • Study the relationship between electric fields and potential differences in parallel plate capacitors
  • Learn about the significance of sign conventions in electromagnetism
  • Explore the concept of electric field direction and its impact on potential calculations
  • Investigate the role of absolute values in physics problem-solving
USEFUL FOR

Students studying electromagnetism, physics educators, and anyone seeking clarity on electric potential differences and field calculations.

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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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