In Act II, the Stage Manager takes us to the time when he says George and Emily's relationship started. What do we learn on Emily's twelfth birthday that shows their relationship began well before the drugstore scene?

that is true because that is something they fulfill for their work.

3 is blunder, i’m not sure about the last one but the first two look correct

the direction of the magnetic field produced by an electric current will change when the direction of the electric current changes. for example : if a current is flowing in a straight length of wire, the magnetic field is described by a concentric circle (using right-hand rule).