Hey ! can anyone help me ?

Giving out 50 points for it ~

What color of light must blue light mix with to create white light? a. yellow b. white c. blue d. green

How would a small bar magnet be oriented when placed at position x?

Electromagnetic induction. a coil of wire contains n turns and has an electrical resistance r. the radius of each turn is a. initially, inside the coil there exists a uniform magnetic field of magnitude b0 parallel to the axis of the coil. the magnetic field is then reduced slowly. the current induced in the coil is i. how long does it take for the magnitude of the uniform field to drop to zero?