13. Which one does not belong to the group?
A. gold
B. block of wood
C. book
D. nylon cord
14. Good electrical conductors are generally good conductors of
A. metal
B. sound
C. heat
D. rubber
15. Rubber and plastic are insulators because
A. They do not allow electrical charge to flow.
B. They do not break.
C. They do not get hot.
D. They do not get damaged
16. They are materials that do not allow light to pass through them.
B. translucent C. shadow
D. none of the above
A. Opaque
17. What is formed when light is blocked?
B. angles
C. shadow
D. different shapes
A. rays
18. How does light travel?
A. in a curve
C. in a circle
D. in a loop
B. in a straight line
19. Objects are not clearly seen through these materials because they blur the light that
hrough them.
A transparent B. translucent
C. opaque
D. clear glass​