Question

A child bought a balloon which became very small in size the next day. Which is the correct statement about the balloon?
A) It is an isolated system.
B) It is an open system.
C) It is a closed system.
D) It exchanges only energy with the surroundings.

Answer 1

Hint: A part of the universe which is under observation of the observer is called the system. So we can say that the system and its surroundings together constitute the universe. There are various types of systems depending upon their ability to exchange matter and energy with the surroundings.

Complete answer:
There are three main types of systems depending upon the kinds of exchanges that can take place between them and their surroundings. They are:
> Open System: It is a type of system in which both matter as well as energy can be exchanged with the surroundings. Its boundary is not closed from all sides.
> Closed System: It is a type of system which can only exchange energy with the surroundings through its boundaries but no exchange of matter can take place. Its boundary is closed from all sides but the walls are not insulating.
> Isolated System: It is a type of system which can neither exchange matter nor energy with the surroundings because it is closed from all sides and its walls are made up of insulating material, hence, disallowing it to exchange either matter or energy with the surroundings.
> So, as per the given question, the balloon becomes small in size because the gas filled inside the balloon diffuses out with time. Hence, it exchanges matter with the surroundings. Also, since it does not happen to have an insulating boundary, hence, it is an example of an open system.

So, the correct option would be (B).

Note: Students should not suppose that since the size of the balloon is reducing only, hence it is exchanging matter with the surroundings only. Since it has not been mentioned, we always have to think in the general case scenario where a balloon has non-insulating walls.