Which best describes an example of an n-type semiconductor? O It uses phosphorus so that electrical conduction is due to the movement of electrons.
O It uses phosphorus so that electrical conduction is due to the movement of a positive charge.
O It uses gallium so that electrical conduction is due to the movement of electrons.
O It uses gallium so that electrical conduction is due to the movement of a positive charge.

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.