For example, you can make an analogy with the flow of water in a tube.
For the sustained flow of charge in a wire, an analogous condition is the continuous movement of water in a pipe, where the pipe needs to be unobstructed and there must be a constant pressure or voltage difference to drive the flow. In the case of electrical current, the wire must be unbroken and there must be a continuous voltage (potential difference) provided by a source such as a battery.
For the sustained flow of water in a pipe, there must be a continuous pressure difference driving the water from a high-pressure area to a low-pressure area. Similarly, for sustained flow of electric charge in a wire, there must be a continuous voltage difference (or electric potential difference) between two points in the circuit, which drives the flow of electrons from the negative terminal to the positive terminal. Both scenarios rely on a gradient—pressure for water and voltage for electric charge—to maintain flow.
The necessary condition for the sustained flow of charge in a wire is the presence of a closed circuit or path for the current to flow in. This closed path allows the charges to continuously move and circulate through the wire. Additionally, an external source of electromotive force, such as a battery or a power supply, is required to provide the energy needed to maintain the flow of charge.
In order for charge to flow, there must be a potential difference present across a conductor. This difference in electric potential creates an electric field that drives the movement of charge through the material.
negative pressure is needed for a sustained flow of water in a pipe.
A potential difference, or voltage, is necessary for a sustained flow of electric charge through a conducting medium. This potential difference creates an electric field that pushes the charges through the conductor. Without a potential difference, the charges will not move and no current will flow.
A potential difference (voltage) across the conducting medium is necessary for a sustained flow of electric charge. This potential difference creates an electric field that pushes the charges through the conductor. Without a potential difference, there would be no force to maintain the flow of charges.
By the application of a voltage source electric charge will flow.
The flow of water in a pipe is analogous to the flow of charge in a wire as both involve the movement of particles through a medium. In a pipe, water molecules move due to a pressure difference, while in a wire, charges move due to a voltage difference. Both systems exhibit resistance to flow, which can be influenced by factors such as pipe diameter or wire material.
A pressure difference between two points along the pipe is necessary for the sustained flow of water. This pressure difference creates a driving force that pushes the water through the pipe, overcoming frictional resistance and allowing for continuous flow.
A medical condition analogous to a closed valve is heart valve stenosis. In this condition, one or more heart valves become narrowed, impeding blood flow and causing the heart to work harder to pump blood. This can lead to symptoms like fatigue, shortness of breath, and chest pain, much like the inefficiency caused by a valve that fails to open properly.
A common condition analogous to the valve above the collecting duct being shut off is dehydration. Just like a shut-off valve prevents water flow, dehydration reduces the flow of urine through the collecting duct. In both cases, the result is a decrease in urinary output.