Question

The coefficient of mutual induction is 2 H and induced e.m.f. across secondary is 2 kV, Current in the primary is reduced from 6 A to 3 A. The time required for the change of current is ____________.

Options

• 3 x 10^-3 s

• 5 x 10^-3 s

• 4 x 10^-3 s

• 6 x 10^-3 s

Answer 1

The coefficient of mutual induction is 2 H and induced e.m.f. across secondary is 2 kV, Current in the primary is reduced from 6 A to 3 A. The time required for the change of current is 3 x 10^-3 s.

Explanation:

`"e"_"s" = "M". "dI"_"p"/"dt"`

`therefore "dt" = "M". "dI"_"p"/"e"_"s"`

`therefore "dt" = 2 xx 3/(2 xx 10^3)`

`= 3 xx 10^-3  "s"`