Question

A glass rod and a plastic straw, both are rubbed with a polythene sheet and brought to each other. Attraction is observed. What kind of charge is acquired on the plastic straw?
A) Positive
B) Negative
C) Neutral
D) Can be any charge

Answer 1

Hint: Here we have to apply the concepts of electric charge.
Electric charge is the fundamental property of electrons, protons and other subatomic particles. It allows electrons and protons to stick together to form atoms. Stuff that have the same charge drive each other further (repel each other). It's called the Law of Charges.

Complete step by step answer:
According to Coulomb, the electric force for charges at rest has the following properties: like charges, they repel each other; unlike charges, they draw. Thus, two negative charges repel each other, while a positive charge absorbs a negative charge. The attraction or repulsion takes place along the line between the two charges.

The protons are much stronger and heavier than the electrons. All of these electrons have a negative charge such that their lines of force are repulsed. Like charges repel, unlike charges attract. Two electrons appear to repel each other because they both have a negative electrical charge.

Electrons may be used to move from one object to another. For example, when a plastic rod is brushed with a duster, electrons are moved from one substance to another. The substance that gains electrons is negatively charged. The substance that lacks electrons is positively charged.

As glass rod and plastic straw are both rubbed with polythene sheets and carried to each other attraction is found between them as glass rod becomes positively charged and plastic straw becomes negatively charged.

Hence, option (B) is correct.

Note: Here we should see on what material the glass rod and plastic straw are rubbed. If the material would have been something else other than polythene, then the answer would have been different.