Joe sets up a light source, concave lens, and screen. He asks you where he should put the screen so that he can project the image on the screen. What do you tell him?

If you put a helium-filled balloon in the refrigerator, what will happen?

Athin nonconducting rod with a uniform distribution of positive charge q is bent into a circle of radius r. the central perpendicular axis through the ring is a z-axis, with the origin at the center of the ring. a) what is the magnitude of the electric field due to the rod at z = 0? n/c (b) what is the magnitude of the electric field due to the rod at z = infinity? n/c (c) in terms of r, at what positive value of z is that magnitude maximum? r (d) if r = 4.00 cm and q = 9.00 µc, what is the maximum magnitude? n/c

What is the relationship between ozone and smog?