The current in the bulb will stop flowing:
if the circuit is broken
Understanding Current Flow in an Electric Circuit
Current flows in an electric circuit when there is a complete path for the electricity to travel from the power source, through the components (like a bulb), and back to the source. This complete path is called a closed circuit. If this path is broken or interrupted at any point, the current stops flowing.
Analyzing the Options for Stopping Current
Let's look at the given options to understand when the current in the bulb will stop flowing:
- Option 1: when the conductor is on
A conductor is a material that allows current to flow easily. The phrase "when the conductor is on" doesn't describe a state of the circuit that would stop current. Conductors are necessary for current flow, not for stopping it. - Option 2: if the circuit is broken
A broken circuit means there is a gap or interruption in the path that the current needs to follow. This break prevents the complete flow of charge from the source to the bulb and back. Therefore, if the circuit is broken, the current will stop flowing, and the bulb will not light up. - Option 3: when the switch is turned on
A switch in a circuit is used to make or break the connection. Turning a switch 'on' usually means closing the circuit, creating a complete path for the current to flow. When the switch is on, the current will flow, and the bulb will light up (assuming the circuit is otherwise functional). So, turning a switch on does not stop the current. - Option 4: if there is magnetic field
While magnetic fields and electric currents are related (as described by electromagnetism), the presence of a magnetic field alone does not inherently stop the flow of current in a simple bulb circuit. Current can flow perfectly fine in a wire or through a bulb even when a magnetic field is present.
Conclusion on Stopping Current Flow
Based on the analysis of each option and the principles of electric circuits, the current in the bulb will stop flowing precisely when the complete path of the circuit is interrupted. This state is described as the circuit being broken.
Revision Table: Circuit Conditions and Current Flow
| Circuit Condition | Current Flow? | Bulb Status |
|---|---|---|
| Circuit is Complete (Closed) | Yes | Lights Up |
| Circuit is Broken (Open) | No | Does Not Light Up |
| Switch is ON (Completes Circuit) | Yes | Lights Up |
| Switch is OFF (Breaks Circuit) | No | Does Not Light Up |
Additional Information: Components of a Simple Circuit
A simple electric circuit typically consists of:
- Power Source: Provides the energy (voltage) to push charges through the circuit (e.g., battery, power supply).
- Conductors: Materials through which current flows easily (e.g., wires).
- Load: The component that uses the electrical energy (e.g., bulb, resistor, motor).
- Switch (Optional): A device used to intentionally make or break the circuit.
For current to flow continuously, these components must be connected in a way that forms a continuous, unbroken loop, creating a closed circuit.
Important Questions from Electric Current
The work done in moving a charge of 2 coulomb (C) from point A to point B is 24 J. What is the potential difference between A and B?
Two conducting wires of the same material and of equal lengths and equal diameters are first connected in parallel and then in series in a circuit across the same potential difference. The ratio of heat produced in parallel and series combinations is
Direction of flow of electric current is from
- A constant potential difference is applied across a metallic conductor of non-uniform cross-section. If the cross-sectional area at section P is $A_P$ and at section Q is $A_Q$, and given that $A_P > A_Q$, which of the following statements is correct?
If 20 Coulombs of charge passes a point in a circuit in 1 second, what is the value of the current flowing?
