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Is the emf of a cell equal to the total potential drop in the external circuit of the cell?
The EMF of a cell is the voltage across the terminals at zero current. This is the quoted cell voltage but as soon as a current is dawn from the cell, the voltage will drop. It's due to the internal resistance of the cell.
In a circuit diagram, a cell is often shown as a voltage source (a perfect source) and a resistor in series to represent the internal resistance. Using Ohms Law, it can be seen that as soon as a current flows, a voltage will be developed across the internal resistance, so reducing the voltage that is seen at the terminals of the cell. The higher the current draw, the higher the voltage drop inside the cell.
Normally, the voltage drop is minimal but in most cells, as it loses charge, the internal resistance rises. Eventually it will reach the point where most of the voltage is dropped across the internal resistance, leaving little to drive the intended load. Often, if a battery is removed from a device and measured, the voltage will be measured as equal to or very close to the quoted cell voltage. It is easy to make a judgment that a battery is good when it is almost dead. The only way to confirm the state of the battery is to measure the voltage at the terminals while the load is attached. The results can be very different to the off load voltage.
Alkaline cells have a low internal resistance compared to other dry cells. This makes them well suited for high current drain applications. The internal resistance also rises more slowly than most other cells, so they remain useful far longer than zinc-carbon types.
What else can I help you with?
How is the total resistance in a series circuit is determined?
The total resistance in a series circuit is determined by adding (summing) the individual resistances of each component in the circuit.
What is the formula for total current in a series circuit?
Current = (Voltage across the circuit) divided by (Total resistance of the circuit). The current is the same at every point in the series circuit.
The sum of the voltage drops around a series circuit is the voltage source input.?
Yes, in a series circuit, the sum of the voltage drops across each component equals the total voltage supplied by the voltage source. This principle is a manifestation of Kirchhoff's Voltage Law, which states that the total voltage around a closed loop must equal zero. Therefore, the voltage provided by the source must equal the combined voltage drops across all components in the circuit.
What is the relationship between the potential difference across a battery and the potential difference across each load in a parallel circuit?
Without specifics (are all the batteries end to end or are some loads between batteries, are all the loads the same resistive, capacitive or inductive value...), the generic answer is: the sum of supplied voltages must equal the sum of voltage drops across the loads.
What happens as a current flows through a parallel circuit?
if the circuit is a series circuit (all loads wired in a single line , one after the other ) then the current will be the same in any part of the circuit . if there are several different paths for the current to take , then each path will carry a different percentage of the total current . when each of these different current values are added together , they will equal the total supplied current.
What is the potential voltage across the circuit components in a series circuit?
In a series circuit, the potential voltage across the circuit components adds up to the total voltage of the circuit.
Why does the potential difference change in a series circuit?
In a series circuit, the total potential difference provided by the power source is divided among the components in the circuit. As current flows through each component, there is a voltage drop across each one. This results in a reduction of potential difference as you move along the circuit.
What is the relationship between EMF and potential difference in an electrical circuit?
The relationship between EMF (electromotive force) and potential difference in an electrical circuit is that EMF is the total energy supplied by a source, while potential difference is the energy transferred per unit charge as it moves through the circuit. In simpler terms, EMF is the total push provided by the power source, while potential difference is the push experienced by the charges as they flow through the circuit.
What is the three laws of parallel circuit?
The potential difference remains the same over the components in parallel and the current splits up proportianally to the components conductances. The components conductances add up to give the combined conductance of the parallel circuit. Conductance is 1 / resistance
What is the resistance in a parallel circuit?
R=1/(1/ R1 +1/ R2 +1/ R3 +.........) Where R is the total external resistance(effective resistance) in an electric circuit.
What is a resistance in a parallel circuit?
R=1/(1/ R1 +1/ R2 +1/ R3 +.........) Where R is the total external resistance(effective resistance) in an electric circuit.
Why would another component effect the electrical current in a series circuit?
All the components in a circuit have a potential effect on the total current used by the circuit. You have to be more specific to get a more precise answer.
Potential energy plus kinetic energy equal what?
Mechanical energy is equal to potential energy plus kinetic energy in a closed system. The total mechanical energy is conserved.
In a parallel circuit does the power of each branch add up?
Yes, the total power dissipated through the circuit is equal to the sum of the power of each branch in a parallel circuit.
Are kinetic and potential energy equal in a system?
In a closed system, the total amount of kinetic and potential energy remains constant, but they are not necessarily equal at any given moment.
Is the current in one branch of a parallel circuit more than less than or equal to the total current?
its less then the total current
What is total minus energy kinetic energy is equal to?
Total minus kinetic energy is equal to potential energy. Potential energy is the energy stored in an object due to its position or state, while kinetic energy is the energy of motion.
