A continuous and closed path of an electric current is called an electric circuit. An electric circuit consists of electric devices, source of electricity and wires that are connected with the help of a switch.

The unit of electric current is ampere (A). 1 A is defined as the flow of 1 C of charge through a wire in 1 s.

One electron possesses a charge of 1.6 ×10^-19 C, i.e., 1.6 ×10^-19 C of charge is contained in 1 electron.

∴ 1 C of charge is contained in  1 / 1.6 x 10^-19

= 6.25 x 10¹⁸ = 6 x 10¹⁸

Therefore, 6 x 10¹⁸ electrons constitute one coulomb of charge.

Any source of electricity like battery, cell, power supply, etc. helps to maintain a potential difference across a conductor.

If 1 J of work is required to move a charge of amount 1 C from one point to another, then it is said that the potential difference between the two points is 1 V.

The energy given to each coulomb of charge is equal to the amount of work which is done in moving it.
Now we know that,
Potential difference = Work Done/Charge

∴ Work done = Potential difference × charge
Where, Charge = 1 C and Potential difference = 6 V

∴ Work done = 6 × 1
= 6 Joule.

The resistance of a conductor depends upon the following factors:
→ Length of the conductor
→ Cross-sectional area of the conductor
→ Material of the conductor
→ Temperature of the conductor

The current will flow more easily through thick wire. It is because the resistance of a conductor is inversely proportional to its area of cross – section. If thicker the wire, less is resistance and hence more easily the current flows.