Good Riddles

Question: What can be white and yellow at the same time?

Question: A powerful spell, the naive knows it well; one cast at an affair for your most popular gown. No sticks, no stones, a mage sans tomes, a fight, no toil but it still breaks you down.

Question: At low tide 14 rungs of a ship are above the water, the rungs are 15 centimeters apart. each 15 mins the water rises 15 centimeters. after 2 hours and 30 mins how many rungs are above the water?

Question: A spirited jig it dances bright, Banishing all but darkest night. Fire can't kill it but water can. Share it, it won't get less unless wind will ruin it.

Question: The person who buys me doesn't need me, the person who makes me doesn't want me, and the person who uses me can't appreciate me.

What am I?