What factor will the electric force between 2 charged objects change if the charge of one object is quadrupled

Asun-sized star will spend most of its lifetime as a: white dwarf red giant protostar main-sequence star

The focal length of a relaxed human eye is approximately 1.7 cm. when we focus our eyes on a close up object, we can change the refractive power of the eye by about 16 diopters. (a) does the refractive power of our eyes increase or decrease by 16 diopters when we focus closely? explain. (b) calculate the focal length of the eye when we focus closely.

How will the system respond to a temperature increase?