Amaterial through which a current does not move easily is a(n)

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.

Explain why electric current cannot exist if a current doesn't have a voltage source.

Ryan is examining the energy of the particles in a bar of gold. what is ryan most likely studying?