This should be pretty basic but I want to clarify some:

I = dQ/dt, so that means that I is the derivative of q(t) right?

So if I'm given q(t) = (7t^2 - 2t +3) pC and told that time is dimensionless for simplicity.

So to solve it I would take the derivative and get 14t-2 (units? pC/time?) Am I doing this right? How would I determine the unit for the answer if t is dimensionless?


If you are not given units of time then you can't calculate amperes. If the units in your problem are actually seconds then the units for your answer would be pA. Without a unit for time I guess the best you could say is pC/time, as you did. I don't understand how saying that time is dimensionless makes any sense or simplifies the problem.

  • \$\begingroup\$ That was my thinking, I just got more confused without units to work with. But other than that, right idea? \$\endgroup\$ – Daniel B. Sep 1 '13 at 17:19
  • \$\begingroup\$ Yes, I think you understand it correctly. \$\endgroup\$ – Joe Hass Sep 1 '13 at 17:24

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