Wondering if anyone can help me on the last problem on the web assign, number 16. Gives us an equation for E in terms of t and wants to know the maximum displacement current through a 1m^2 area perpendicular to E. I used the equation current equals epsilon not times the derivative of electric flux (integral of E dot dA) with respect to time. That becomes current equals epsilon not times area times the derivative of E with respect to time, which is the equation we are given. When taking the derivative of E = .05sin(1900t), I came up with (.05)cos(1900t)(1900). Since the max of cos(1900t) is 1, I just multiplied (.05)(epsilon not)(1900) and my answer was not correct.

I looked on the answer key and saw that when you took the derivative of your function .01sin(1900t), you got cos(1900t)(1900) without the .01 in front, so ultimately, your answer is just epsilon not times 1900. Is that right?

Hi Keri -- the .01 (or .05 in your case) didn't go away, I just multiplied it in with the permittivity of free space. Sounds like you're on the right track... if you're still stuck, post the actual problem and we'll take a look at it!

Sure enough, I used the wrong value for epsilon not. Sorry about that! Thanks!

Glad you got it sorted out... have a great weekend!