What is the emf of a cell equal to?
Electromotive force (EMF) is equal to the terminal potential difference when no current flows. EMF and terminal potential difference (V) are both measured in volts, however they are not the same thing. EMF (ϵ) is the amount of energy (E) provided by the battery to each coulomb of charge (Q) passing through.
Is it possible that the terminal potential difference across the cell be zero?
Yes,terminal potential difference V=lR . If external resistance R=0,V=0i,e terminal potential difference is zero,when cell is short circuited.
Is it possible that any cell has some constant?
Yes, if another identical battery is joined in series.
What happens if a battery has no potential difference?
When there is no potential difference in the circuit, then no current will flow. But in the case of a short circuit, will the current flow? If the voltage across a circuit is quadrupled, what is the current through the circuit? If the potential difference is zero, will current flow across two ends of a circuit?
Why Terminal potential difference is greater than EMF during charging?
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.
At what condition terminal potential is greater than EMF?
V=E-Ir, IF I is negative, then V>E, i.e., the terminal potential difference of the cell is more than its emf. This occurs if other cells in the circuit causes current to flow through the given cell from its positive electrode to negative electrode. Which is opposite to the direction in which current flows in a cell.
Why terminal voltage is more than EMF?
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.
Why is terminal PD less than EMF?
1 Answer. When a cell is in closed circuit, i.e., when current is drawn from it, then the potential difference between its electrodes is called the terminal voltage. It is always less than the e.m.f. because when charge flows in a circuit, some energy is spent in the flow of charge through the electrolyte of the cell.
What is the source of EMF?
EMF is classified as the external work expended per unit of charge to produce an electric potential difference across two open-circuited terminals. Devices that can provide EMF include electrochemical cells, thermoelectric devices, solar cells, electrical generators, transformers, and even Van de Graaff generators.