Question

stretching a rubber band what is the effect of force

Answer 1

Explanation:

Following the relation known as Hooke 's law, a 10% percent increase in stretching force will make a typical rubber band 10% longer. But when rubber materials are stretched to twice their original size or more, that simple linear law fails.

Answer 2

A rubber is typically pretty flexible material (unless it is very old, or frozen in a liquid nitrogen). It will simply elongate (stretch), and the cross-section of the sample will decrease.

See Poisson's ratio

However after a critical material strength is exceeded, the sample will break (snap) and the potential energy of elasticity stored in it will discharge (in your fingers…).