You have two equations: 1st: 1 J = 1 N ∗ 1 m and 2nd: 1 V = 1 C 1 J
from the second equation you can extract Joule: 1 J = 1 V ∗ 1 C you compare right side of the equation above to the right side of the 1s equation: 1 V ∗ 1 C = 1 N ∗ 1 m
then you devide both sides by 1C and by 1m and you get: 1 m 1 V = 1 C 1 N
The units newtons per coulomb (N/C) and volts per meter (V/m) are equivalent as shown through their definitions involving joules, volts, and newtons. By manipulating these definitions, we can derive that 1 N/C = 1 V/m. Therefore, both units represent the same concept in physics.
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