Question

A solenoid of length 50 m and having radius 3 cm and 500 turns, find the unduced emf when the current in solenoid changes from 0 to 5 A in 0.2 s ?​

Answer 1

Answer:

given = length l = 50cm = 0.5 m

            radius = r = 0.03m

           number of turns in solenoid N1 = 500

           number of turns in wire N2 =  50

           change in current  ΔIT = (5 -0) A = 5A

           change in time = Δt = 0.02s

to find = induced emf

solution = mutual inductance (M) = μN1N2A/ l

                                                      = 4π X 10⁻⁷X500 X 50 X 3.14 X (2 X 10⁻²)²

                                                      =  28.26 / 0.5

                                                      =  56.52μH

the emf induced in the solenoid coil is

         ε = -M ΔI / Δt

         ε =56.52X 10⁻⁶ ( 5 / 0.02)

         ε =  56.52 X 10⁻⁶  X 250

         ε = 14.130emv