A source of current is a device that maintains a constant potential difference between two conductors to ensure a continuous flow of current. When conductors at different potentials are connected by a wire, current flows from higher to lower potential until equilibrium is reached, after which the flow stops. To sustain a steady current, a source of current converts non-electrical energy, such as chemical, mechanical, heat, or solar energy, into electrical energy. Common examples include cells (chemical energy), electric generators (mechanical energy), thermocouples (heat energy), and solar cells (solar energy).
What happens when two conductors at different potentials are connected by a metallic wire?
Current flows from the conductor at a higher potential to the one at a lower potential until they both reach the same potential.
Why does the flow of current stop between two conductors after some time?
The flow stops when the potential difference between the two conductors becomes zero (they are at the same potential).
How can a constant current be maintained in a wire?
By connecting the ends of the wire to a source of current that maintains a constant potential difference.
What is the primary function of a source of current?
To convert non-electrical energy into electrical energy and maintain a constant potential difference for a steady flow of current.
Can current flow indefinitely between two conductors without a source of current?
No, current flows only until the potential difference between the conductors is equalized, after which it ceases unless a source of current is present.
When two conductors at different potentials are connected by a wire, current flows until:
a) The wire heats up
b) The conductors reach the same potential
c) The wire breaks
d) The source of current is removed
Answer: b) The conductors reach the same potential
To maintain a constant current in a circuit, what must be ensured?
a) High resistance in the wire
b) Equal potential of the conductors
c) Constant potential difference across the conductors
d) Insulated conductors
Answer: Constant potential difference across the conductors
What is the main function of a source of current?
a) To convert electrical energy into heat energy
b) To maintain a constant potential difference
c) To stop the flow of current
d) To equalize the potential of conductors
Answer: b) To maintain a constant potential difference
Which device converts chemical energy into electrical energy?
a) Solar cell
b) Thermocouple
c) Electric generator
d) Cell
Answer: d) Cell
Which of the following is an example of a source of current that converts heat energy into electrical energy?
a) Electric generator
b) Thermocouple
c) Solar cell
d) Capacitor
Answer: b) Thermocouple