help me for included unit
Chapter 30, Problem 058 Suppose the emf of the battery in the circuit shown in the figure varies
with time t so that the current is given by i(t) 2.005.00t, where i is in amperes and t is in seconds.
Take R = 2.00 ? and L 5.50 H, and find the emf required of the battery at t = 4.00 s. Number
Units
Solution
in accordance with Kirchhoff' law we have in the considered circuit two electromotive forces E
and -Ldi/dt and so
E-Ldi/dt=iR
di/dt = 5
So,
E = iR + L*di/dt
E=((2+5t)x2)+( 5.5x5)
replace t with t=4s in order to find out the electromotive force of the at that very time. We get:
E = 71.5 V