another one of magnetics

Q(1) An inductor is connected to a battery through a switch. Explain why the emf induced in the inductor is much larger when the switch is opened as compared to the emf induced when switch is closed .( not a doubt)

Q(2) A metal sheet is placed in front of a strong magnetic pole. A force is needed to :

(A) hold the sheet there if the metal is magnetic
(B) hold the sheet there if the metal is non-magnetic
(C) move the sheet away from the pole with uniform velocity if metal is magnetic
(d) move the sheet away from the pole with uniform velocity if metal is nonmagnetic

(Neglect any effects of para, ferro, diamagnetism and gravity )

Q(3)An LR circuit with a battery is connected at t =0. Which of the following quantities is not zero just after the connection ?
(a) current in the circuit
(b)magnetic field in the inductor
(c) power delivered in the battery
(d)emf induced in the conductor

PS: all are more than one ans correct .2nd and 3rd q are my doubts