Question

When a plastic rod is rubbed with the fur, what charge does the plastic rod get?
A. Positive
B. Negative
C. Neutral
D. None of the above

Answer 1

Hint: In this question we are asked to find the nature of charge the plastic rod will gain when it is rubbed with the fur. We know that when the plastic rod is rubbed with fur, there is an imbalance of charge on the surface of the rod. This charge that is gained by the rod is called a static electric charge. Therefore, we shall discuss static electric charge and its nature.

Complete answer:
We know that static electricity is the result of imbalance between negative and positive charge in an object. These charges will stay on the object unless they are discharged. We know that materials are made of atoms and are electrically neutral as they have equal numbers of protons and electrons. Static electricity is the separation of these charges. When two materials such as a plastic rod and fur are brought together, the electrons move from one material to another. This leaves excess positive charge on one object and vice versa. When the objects are separated, they retain the respective charge.
In case of the plastic rod and the fur, the negatively charged electrons from fur move to the plastic rod making it negatively charged and simultaneously leaving the fur with concentration of positively charged particles.

So, the correct answer is “Option B”.

Note:
The static electricity sometimes causes a spark, as excess charge is neutralized by flow of charges to the surrounding. We get the feeling of shock by the stimulation of nerves as the neutralizing current flows through our body. The static energy is discharged in less than a microsecond. However small the static energy is it can still damage the sensitive electronic devices.