Units of Coulomb, trouble understanding the question

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    Coulomb Units
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Homework Help Overview

The problem involves calculating the force between two charges, q1 and q2, given their values and distance apart. The subject area pertains to electrostatics and Coulomb's law.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to apply Coulomb's law but questions the interpretation of the charge units, specifically the notation "e C." Some participants clarify the meaning of the elementary charge and its implications for the calculations.

Discussion Status

The discussion has seen attempts to clarify the units involved in the problem. While some guidance has been offered regarding the interpretation of the charge values, the original poster's confusion about the units remains a point of exploration.

Contextual Notes

There is uncertainty regarding the notation used for the charges and whether it requires conversion. The original poster's reference to an online calculator suggests a search for validation of their calculations.

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Homework Statement


Two charges, q1 = 4.9 e C and q2 = -3.6 e C are located 105nm apart, what is the size of the force between the two charges?

Homework Equations



F=kqq/r^2

The Attempt at a Solution



I did it according to the formula and I got the answer wrong, so I checked it using an online force calculator between charges, and it gave the same answer I initially got. I looked up what e C is, thinking maybe it's indicating something smaller than 1 C, and couldn't really find a graduation for that, what am I doing wrong? Is it meant to be multiplied by 1.6 x 10^-19?
 
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Actually [itex]q_1 = 4.9 e C[/itex] is somewhat incorrect. [itex]e = 1.6\times10^{-19}C[/itex] is the elementary charge and already contain the unit Coulomb. So it is as if [itex]q_1[/itex] has unit Coulomb-Coulomb.
 
mathfeel said:
Actually [itex]q_1 = 4.9 e C[/itex] is somewhat incorrect. [itex]e = 1.6\times10^{-19}C[/itex] is the elementary charge and already contain the unit Coulomb. So it is as if [itex]q_1[/itex] has unit Coulomb-Coulomb.

So does this mean that I have to multiply 4.9 by 1.6x10^-19?
 
Nvm, problem(s) solved.
 

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