14. ••• The flux through a loop of wire changes uniformly from +40 Wb to −20 Wb in 1.5 ms.

(a) What is the significance of the negative number attached to the final flux value?

(b) What is the average induced emf in the loop?

(c) If you wanted to double the average induced emf by changing only the time, what would the new time interval be?

(d) If you wanted to double the average induced emf by changing only the final flux value, what would it be?