When does total internal reflection occur?

a. when the angle of incidence exceeds the angle of reflection

b. when the angle of incidence is less than the angle of reflection

c. when the angle of incidence is less than the critical angle

d. when the angle of incidence exceeds the critical angle

Aperson gives a shopping cart an initial push along a horizontal floor to get it moving, and then lets go. the cart travels forward along the floor, gradually slowing as it moves. consider the horizontal force(s) on the cart while it is moving forward and slowing. which of the following statements is correct? (a) both a forward and a backward force are acting on the cart, but the forward force is larger. (b) only a forward force is acting which diminishes with time. (c) both a forward and a backward force are acting on the cart, but the backward force is larger. (d) only a backward force is acting, no forward force.

Convection occurs when thermal energy is transferred by the movement of

An element becomes a positively charged ion when itloses protons. loses electrons. gains electrons. gains neutrons.