How does an insulator stop the flow of an electric current?

a. insulators have too many electrons.

b. insulators have a positive charge so they absorb electrons.

c. electrons in an insulator do not move readily.

d. insulators convert electric energy to other forms of energy.

How does the image distance (di) of a convex lens compare with the image distance of a concave lens? a. the image distance of the convex lens is positive, and that of the concave lens is negative. b. both are negative for a virtual image. c. both are positive for a virtual image d. the image distance of the convex lens is negative, and that of the concave lens is positive.

Write down two additional questions about earth's magnetic field that will make your presentation more informative.

Match these items. 1. coulombs __force 2. ohms __emf 3. centimeters __resistance 4. newtons __charge 5. volts __length