A long thin solenoid has `900"tuns"//"metre"` and radius `2.50cm`,. The current in the solenoid is increasing at a uniform rate of `60A//s`. What is the magnitude of the induced electric field at a point?
a. `0.5cm` from the axis of the solenoid.
b. `1.0cm` from the axis of the solenoid.

Explanation

`:'=B=mu_0ni`
`:. (dB)/(dt)=mu_0n(di)/(dt)`
`=(4pixx10^-7)(900)(60)`
`=0.068T//s`
Using the result of electric field derived in above problem (as both points lie the solenoid).
`E=r/2((dB)/(dt))`
a. `E ((0.5xx10^-2)/2)(0.068)=1.7xx10^-4V//m`
b. `E=((1.0xx10^-2))/2(0.068)=3.4xx10^-4V//m`