Physics help, thank you guys so much!

 Δt = 5.85 s

Explanation:

For this exercise let's use Faraday's Law

           emf = -  d fi / dt

            = B. A

           \phi = B A cos θ

The bold are vectors. It indicates that the area of the body is A = 0.046 m², the magnetic field B = 1.4 T, also iindicate that the normal to the area is parallel to the field, therefore the angle θ = 0 and cos 0 =1.

suppose a linear change of the magnetic field

            emf = - A

             Dt = - A  

the final field before a fault is zero

let's calculate

            Δt = - 0.046 (0- 1.4) / 0.011

            Δt = 5.85 s