**1. The problem statement, all variables and given/known data**

A solenoid has a radius of 1.85 cm and 1110 turns per meter. Over a certain time interval the current varies with time according to the expression I = 2.50t, where I is in amperes and t is in seconds. Calculate the electric field 5.47 cm from the axis of the solenoid.

**2. Relevant equations**

E = (μ[itex]_{0}[/itex]n/2)(di/dt)(R[itex]^{2}[/itex]/r), r>R

Where μ[itex]_{0}[/itex] = 4∏x10[itex]^{-7}[/itex], n = 1110 turns/meter, di/dt = 2.50, R = 0.0185m, r=0.0547m

**3. The attempt at a solution**

After plugging in all the numbers and putting things in the right units, I got 1.09×10[itex]^{-4}[/itex] V/m, but this is incorrect. If someone could tell me where I went wrong, I would really appreciate it! Thanks

http://ift.tt/1oxgY44