At what distance from a convex lens must an object be to get a virtual image?
-at a focal point
-at more than twice the focal length
-greater than the focal length but less than twice the focal length
-at a distance less than the focal length

Patricia is trying to compare the average rainfall of new york to that of arizona. a comparison between these two states for the months of july through september would best be measured in

An electron is ejected into a horizontal uniform e⃗ field at a parallel horizontal velocity of v0. assume the electron's initial position x0, initial velocity v0, time t, magnitude of electric field e, electron's mass m, and the magnitude of the electron's charge |e|. ignore the force that earth exerts on the electron. assume the e⃗ field is in the same direction as the initial velocity. part a define the equation for the electron's velocity. express your answer in terms of the variables v0, |e|, t, e, and m.

Which of the following is part of the explanation or description of electromagnetic waves? (select all that apply) a. electrically charged molecules in a medium transfer their energy to nearby electrically charged molecules. b. a changing electric field causes a changing magnetic field. c. magnetic molecules in a medium transfer their energy to nearby magnetic molecules. d. a changing magnetic field causes a changing electric field.