Question

A closed circuit has its every part made of ________
A. conducting material
B. non-conducting material
C. semi-insulating material
D. None of these

Answer 1

Hint:To solve this question, it is necessary to understand two main concepts viz. concept of open and closed circuit and the categorisation of the materials in terms of electrical conductivity. By putting together these concepts, we can arrive at the answer.

Complete step-by-step answer:
Conductors are the substances that completely allow the electric current to pass through them and insulators or non-conductors are those that completely block the flow of current through them.
In other words, the resistance offered by the conductors is very low and the resistance offered by the insulators are very high.
A circuit can be defined as the path which the electrons take, during its course of electron flow, whose ends are maintained at a finite potential difference known as the terminal voltage of the circuit.
Here is an example of a simple circuit with terminal voltage V connected to a resistance R.

Before we get into the concept of open or close circuit, we will see an important circuit device called switch. The switch is a device which is used to toggle the circuit between open and closed phase.
Consider the same circuit above with switch S added.

In this above condition, we can see that the circuit has been broken by the switch since the current does not form a continuous path. This condition of the circuit is called open circuit.
Now, consider this circuit.

In this diagram, we see that the switch is toggled and the circuit now, forms a continuous and closed path. This condition of the circuit is called closed circuit.
We can see that when the switch is open, there is a separation which acts as a non-conductive material that does not allow the current to pass through.
So, it can be inferred that for a closed circuit, there should be no non-conductive or insulating materials in between and the entire path should be made of conductive materials.

Hence, the correct option is Option A.

Note: Sometimes, when the voltage reaches exceedingly high values, the gap in the switch cannot hold back the circuit and the air or the material undergoes a change known as polarisation. Once, the gap in the switch gets polarised, they start conducting and suddenly, a huge amount of current starts flowing in the circuit. This condition of the circuit is called a short circuit.