2 Phy question (electromagnetic)

Q1:
You have 1kg of copper and want to make a pracical solenoid that produces the greatest possible magnetic field for a given voltage. should you make your copper wire long and thin, short and fat, or something else? concider other variavle, such as solenoid diameter, length and so on.

Answer for question 1 is long and thin.

Q2:
A mas spectrometer is being used to monitor air pollutants. It is difficult, however, to separate molecules with nearly equal mass such as CO (28.0106u) and N2 (28.0134u). How large a radius of curvature must a spectrometer have if these two molecules are to be separated on the film by 0.05mm?

Answer for question 2 is 2.5m