An important difference between insulators and conductors is that in conductors
Question 15 options:

1)

protons can be removed from atoms easily

2)

electrons carry electric charges

3)

electrons are free to move around

4)

all of the above are true

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

People with normal vision cannot focus their eyes underwater if they aren't wearing a face mask or goggles and there is water in contact with their eyes. in a simplified model of the human eye, the aqueous and vitreous humors and the lens all have a refractive index of 1.40, and all the refraction occurs at the cornea, whose vertex is 2.60 cm from the retina.with the simplified model of the eye, what corrective lens (specified by focal length as measured in air) would be needed to enable a person underwater to focus an infinitely distant object? (be careful-the focal length of a lens underwater is not the same as in air! assume that the corrective lens has a refractive index of 1.62 and that the lens is used in eyeglasses, not goggles, so there is water on both sides of the lens. assume that the eyeglasses are 2.05cm in front of the eye.)

Whithin which type of system is neither the total mass nor the total energy conserved ? a. open b. connected c. isolated d. closed