Answer
(a) greater than
(b) less than
Work Step by Step
(a) We know that if the same force is applied then the half spring will stretch a half distance because now there are fewer coils to be compressed or stretched. We know that $K=\frac{F}{x}$, this equation shows that the spring constant and stretching distance are inversely proportional. Thus, the force constant for the half spring will be greater than K.
(b) We know that if the spring length is doubled then the stretched distance will also be doubled. We also know that $K=\frac{F}{x}$ which shows that spring constant and stretched distance are inversely proportional. Thus, if the force remains the same then the spring constant will be less than K.
