Question

During dry weather, clothes made up of synthetic fibre often stick to the skin. Which type of force is responsible for this phenomenon?
A) Electrostatic force
B) Frictional force
C) Intermolecular force
D) None of the above

Answer 1

Hint: To find which type of force caused the sticking of the synthetic cloth to the skin, we have to recollect our knowledge of static charges. Try to find out what charges are being produced while the cloth is in contact with the skin. Also, find out if these charges can have any sort of force between them.

Complete answer:
There are two types of charges known to us: Positive and negative. When two positive or two negative charges come into close vicinity they repel each other. When a positive and a negative charge come into close vicinity, they attract each other. In short, like charges repel each other and unlike charges attract each other.
The synthetic cloth gets charged due to the occurrence of static clinging from static electricity. Due to the triboelectric effect, the electrostatic charges get induced on the clothes when they rub against each other.
When this charged synthetic cloth gets rubbed against the skin, charges are produced which are known as static charges. The force produced by these charges which stick the cloth to the skin is called electrostatic force.
On the other hand, the frictional force is an opposing force. When two objects move in the same or different directions, this force resists their motion. Intermolecular force is the force between two molecules of any element. This force determines the state of the element i.e. whether the element will be in a solid, liquid, or gaseous state.
Hence, option (A) is correct.

Note:
Certain materials get electrified or electrically charged when they are separated from a material with which they were in contact. Such a type of contact electrification is known as the triboelectric effect. For example: rubbing glass with silk rod, rubbing plastic comb through hair.