Simple current and charge circuit question

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Homework Help Overview

The discussion revolves around a problem in the context of electric circuits, specifically focusing on the relationship between current and charge over a specified time interval. The original poster presents a current function and seeks to determine the total charge that passes a point in a circuit.

Discussion Character

  • Exploratory, Conceptual clarification

Approaches and Questions Raised

  • The original poster attempts to calculate the charge by evaluating the current at specific time points, leading to confusion regarding the expected answer. Some participants suggest integrating the current function to find the total charge, while others express uncertainty about the necessity of integration.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the problem. Some guidance has been offered regarding the integration of the current function, but there is still a lack of clarity for some participants about the underlying concepts.

Contextual Notes

The original poster mentions a discrepancy between their calculated charge and the answer provided in a reference, indicating potential misunderstandings about the relationship between current and charge over time.

JFonseka
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Homework Statement


If the current in a wire is given by the following functions of time, what charge passes
a given point from t=0 to t=10 seconds? (i is in Amps and t in seconds). Show units
for charge.

i(t) = 4t + 5


Homework Equations



Nothing really

The Attempt at a Solution



0 seconds: 5A
10 seconds: 4x10 + 5 = 45A

Therefore 50C have passed through the wire in total.
But the answer at the back for my question says 250C, I don't get it.
 
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You have to integrate that formula with respect to time, then plug in a value for t.
 
Ah...now I see that I get the right answer...but why do we have to integrate. I don't get it.
 
Nvm I just realized. This is what happens when you stay out of touch with physics for 4 months.
 

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