Question

When a Soap bubble is charged
A.) It Contracts
B.) It Expands
C.) It does not go any change in size
D.) None of these

Answer 1

Hint: A soap bubble is filled with air inside it and the surface has the molecules of soap water. This membrane acts like an elastic or stretchable surface due to the surface tension of liquid. This membrane is the only layer present in soap bubbles and all the molecules are present only on the surface of a soap bubble.

Complete answer:
Since a soap bubble has molecules present only on its surface so we can say that when we provide charge to a soap bubble it will be distributed only on the surface of the bubble because this is the only layer where molecules are present. When molecules gain charge their tendency to attraction and repulsion increases and since we have provided only one type of charge to the whole surface, so all the molecules will start to repel each other because the same type of charges repel each other and hence its radius will increase and the soap bubble will expand and grow bigger.
So, we can conclude that when we provide charge to a soap bubble it will start expanding and its radius will increase.

So, Option (B) is the correct answer.

Note:
When we provide a charge to some object then an opposite charge will also induce this is to oppose the cause of change, here in the case of bubble also there will be an induction of charge opposite to what is provided but this will not be available on the surface and hence the bubble have only air inside it so the force of repulsion will be greater and hence the soap bubble expands.