- #1
ryanwilk
- 57
- 0
Hi, just to check which equation for Jd (the displacement current density) is correct:
1) Jd = ε0εr(dE/dt), or
2) Jd = ε0(εr-1)(dE/dt)
1) came from the fact that Jd = ε(dE/dt) and ε=ε0εr
2) came from differentiating P = ε0(εr-1)E (since Jd=dP/dt).
It's only a minor thing but in a question I'm doing, it gives a different answer to 1 s.f. so you can't really just say that εr = εr-1.
Thanks.
1) Jd = ε0εr(dE/dt), or
2) Jd = ε0(εr-1)(dE/dt)
1) came from the fact that Jd = ε(dE/dt) and ε=ε0εr
2) came from differentiating P = ε0(εr-1)E (since Jd=dP/dt).
It's only a minor thing but in a question I'm doing, it gives a different answer to 1 s.f. so you can't really just say that εr = εr-1.
Thanks.