Question

Choose the symbol of variable resistance:

A.

B.

C.

D.

Answer 1

Hint: We will take the help of definitions along with their symbols. By G we can understand the galvanometer and the bulb is what we can see in our daily life. We will consider the difference based on the arrow in the simple fixed resistance and the variable resistance.

Complete answer:
A. Fixed resistance: The definition of fixed resistors totally depends upon the name of it. Simply we can define that fixed resistance is the resistance which never changes. In fact the resistance remains fixed by making the change in temperature and voltage. The diagram of fixed resistance is as below.

B. Galvanometer: The galvanometer is a technical device which when attached in the circuit provides us with the correct value of the current flowing in that circuit. Even circuits having very small currents flowing in them give readings with the help of a galvanometer. The following is the correct diagram for the galvanometer.

C. Variable resistance: As the name suggests, the variable resistor changes in resistance but it is according to the current flowing in it. This helps in controlling the current by providing enough resistance to the circuit. Variable resistance also controls voltage across two devices. The figure below shows the right diagram for variable resistance.

D. Bulb: A bulb is something which can be seen in our daily lifestyle. The bulb is an object which when connected to a circuit emits light after switching on the switch. It consists of a vacuum in its enclosure which helps in protecting the circuit inside it. This circuit can bear high temperature and it converts electricity into heat energy. The following is the diagram for the bulb.

So, the correct answer is “Option C”.

Note:
We will come across some definitions which have a meaning hidden in their names only. For example the terms variable resistance and fixed resistance are the terms which can be understood by their names. Maybe that is why they have been marked like so. All devices discussed here are helpful for circuits in one way or the other. There can be confusion between the diagrams of fixed resistance and variable resistance. The only arrow in the variable resistance differentiates the two with each other. One can get confused between these two terms so, this is because the arrow is important.