(a) voltage source, resistor and
switch
(b) voltage source and a conductor
(c) power source and a bulb
(d) voltage source, conductor, ammeter and switch
Correct Answer: (b)
Explanation
A potential difference and
a conducting path are sufficient to cause current flow.
Notes for
More Information
Conditions Required for Electric Current Flow
- To allow electric
current to flow, two basic things are required:
- A voltage
source
- A conductor
- Electric current is defined as
the rate of flow of electric charge.
Role of Voltage
- When a voltage is
applied across a conductor, it creates a potential difference.
- This potential
difference provides the driving force for electrons.
- As a result, electrons
move from higher potential to lower potential, producing electric
current.
Voltage Source
- A voltage
source (such as a battery or generator) provides the electrical
energy needed to move charges.
- It acts like a push that
forces electrons to flow through the circuit.
Conductor
- A conductor (such
as a metallic wire) provides a path for electrons to
move.
- It ensures a closed
and continuous path for current flow.
Why Other Options Are Incorrect
(a) Voltage source, resistor,
and switch
10. A resistor is a load that limits current, but it is not
a minimum requirement for current flow.
11. A switch only controls (opens or closes) the circuit and
is not essential for current to exist.
(c) Power source and a bulb
12. A power source is essentially a voltage source.
13. A bulb is a load (resistor) and is not mandatory for
current flow.
14. Also, conductors (wires) are still required to complete
the circuit.
(d) Voltage source, conductor,
ammeter, and switch
15. An ammeter is used only to measure current.
16. A switch is a control device.
17. Neither the ammeter nor the switch is necessary for the basic flow
of current.
Conclusion
- The minimum
requirements for electric current flow are:
- A voltage
source
- A conductor
