The magnetic flux of `phi` (in weber) in a closed circuit of resistance `3 ohm` varies with time `t` (in second according to the equation `phi = 2 t^(2) - 10 t` at `t = 0.25 s`?

Answer

3

Explanation

Here, `R = 3 Omega, phi = 2 t^(2) - 10 t +3, I = ?, t = 0.25 s`
`e = - (d phi)/(dt) = - (d)/(dt) (2 t^(2) - 10 t + 3)`
`e = - 4 t + 10`
At `t = 0.25 s, e = - 4 xx 0.25 + 10 = 9` volt
`I = (e)/(R ) = (9)/(3) = 3 A`