Acamera gives a proper exposure when set to a shutter speed of 1/250 s at f-number f8.0. the photographer wants to change the shutter speed to 1/1000 s to prevent motion blur. to maintain proper exposure, she should also change the f-number the answer is f4.0.

Copper has free electrons per cubic meter. a 71.0-cm length of 12-gauge copper wire that is 2.05 mm in diameter carries 4.85 a of current. (a) how much time does it take for an electron to travel the length of the wire? (b) repeat part (a) for 6-gauge copper wire (diameter 4.12 mm) of the same length that carries the same current. (c) generally speaking, how does changing the diameter of a wire that carries a given amount of current affect the drift velocity of the electrons in the wire?

Identify the theory that can be used to explain each phenomenon. answers diffraction: wave theory interference: wave theory reflection: both particle and wave theories refraction: both particle and wave theories

What is the coefficient of kinetic friction μk between the block and the tabletop?