What is the formula for induced emf?
An emf induced by motion relative to a magnetic field is called a motional emf. This is represented by the equation emf = LvB, where L is length of the object moving at speed v relative to the strength of the magnetic field B.
Is EMF a force or work?
Electromotive force is defined as the electric potential produced by either electrochemical cell or by changing the magnetic field. EMF is the commonly used acronym for electromotive force. Therefore, an electromotive force is a work done on a unit electric charge.
Is EMF equal to voltage?
Emf is not a force at all; it is a special type of potential difference. To be precise, the electromotive force (emf) is the potential difference of a source when no current is flowing. Units of emf are volts.
What is the difference between voltage and EMF?
Emf is the voltage developed between two terminals of a battery or source, in the absence of electric current. Voltage is the potential difference developed between the two electrode potentials of a battery under any conditions.
How is EMF greater than potential difference?
The emf of a cell is always greater than its terminal voltage. Because emf is the potential difference across the two terminals of a voltage source when it is not connected to any circuit. And once it is connected to a circuit, the voltage reduces slightly because of the internal resistance of the voltage source.
Why EMF is more than potential difference?
The emf of a cell is greater than its terminal voltage because there is some potential drop across the cell due to its small internal resistance.
Is EMF always positive in cells?
The maximum potential difference which can be measured for a given cell is called the electromotive force, abbreviated emf and represented by the symbol E. By convention, when a cell is written in shorthand notation, its emf is given a positive value if the cell reaction is spontaneous.
What is the difference between potential and EMF?
The potential difference is the measure of energy between any two points on the circuit. The EMF is the maximum voltage that the battery can deliver whereas the magnitude of the potential difference is always less than the maximum possible value of emf.
Why is terminal voltage is less than its EMF?
The so-called terminal voltage of a battery is lower than the emf when it is discharging because of the voltage drop across the internal resistance.
Which condition EMF of cell is less than of terminal voltage?
Because emf is the potential difference across the two terminals of a voltage source when it is not connected to any circuit. And once it is connected to a circuit, the voltage reduces slightly because of the internal resistance of the voltage source.
Why is terminal voltage of the cell?
Terminal voltage is always lesser than the emf of the cell. It is because of the drop in potential difference because of the current passing through the internal resistance of the cell or the generator. They are related by the equation E=V+Ir, where, I is the current and r is internal resistance of the cell.
Why the emf of a cell is always greater than its terminal voltage?
The emf of a cell is greater than terminal voltage because the potential difference between the two terminals is not connected to any of the circuit. If it connects to the circuit then the voltage is automatically reduced because of the internal resistance.
Can Terminal PD be greater than EMF of a cell?
The value of terminal potential difference of a cell becomes greater than the emf of the cell during charging the cell, i.e., wehn the positive electode of the cell is connected to positive terminal of battery charger and nagative electrode of the cell is connected to negative terminal of battery charger.
In which condition terminal voltage of a cell will be greater than EMF of cell?
Reason: The emf of a cell is always greater than its terminal voltate. Solution : During charging, E=V+ir (due to reversed current). In case of charging emf of a cell is less than its terminal voltage while in case of discharging emf Is is greater than terminal voltage.
Can the PD across a cell be greater than its EMF?
The potential difference across a battery cannot be greater than its emf. Basically, emf is the maximum potential difference between the terminals of a battery when the terminals are not connected externally to an electric circuit.
In what conditions are EMF and PD equal?
The electromotive force (e) or e.m.f. is the energy provided by a cell or battery per coulomb of charge passing through it, it is measured in volts (V). It is equal to the potential difference across the terminals of the cell when no current is flowing.
What is the relation between EMF E and PD V of a cell when it is charging?
So the total applied potential difference across the cell must be V=E+IR. It might be clearer if both sides of the equation are multiplied by the current VI=EI+I2R. Now VI is the power being delivered by an external source to the cell.
Can EMF be less than terminal voltage?
Yes it can, for example when a cell is being recharged the terminal pd is V=E+IR where E is the emf of the cell, I is the current passing through the cell from positive to negative terminal and R is the internal resistance of the cell.