Rubber is ___but glass is ___
opaque
transparent
A glass rod is rubbed with a silk cloth and an inflated rubber balloon is rubbed with a woollen cloth.
Now, out of glass rod, silk cloth, rubber balloon and woollen cloth:
(a) Which two objects acquire negative charge?
(b) Which two objects acquire positive charge?
What is common in a rubber ball, a football and a glass marble?
Make a classification key for the following groups of substances. a. rubber, paper, steel plate, glass.