To separate a mixture of hard candies and marbles, the most efficient method would be

I think hand picking is best for this case.another method can be done in which first u have melt those candies with marbles.u will hart candy will melt quickly.so,when candies melt ,u will find marbles are still solid but candies are in liquid form .now take a net and purify that solution(candies and marbles).now the candies will pass through net but marbles will stuck in upper net.remove marbles now

Determine the  wavelength of light emitted when an electron  in an li2+ ion  makes a transition from an orbital with n  =  6 to an orbital with n  = 5.