What is a terminal PD?
the terminal p.d. is the enrgy transferred per coulomb from electrical into other forms in the external circuit. All you need to remember is that EMF = V when I = 0. when you draw current from a power supply the p.d. across its terminals falls. The more current you draw the more it falls.
Why is the emf of a cell greater than the 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.
Why is EMF of the cell always positive?
By convention, when a cell is written in shorthand notation, its emf is given a positive value if the cell reaction is spontaneous. That is, if the electrode on the left forces electrons into the external circuit and the electrode on the right withdraws them, then the dial on the voltmeter gives the cell emf.
When a cell is undergoing charging process?
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.
What is charging of cell?
Discharging or charging is always occurring inside a battery at any given time. This causes the battery to discharge or produce electrical energy. This excess electron flow out of the negative side of the battery, through the electrical device, and back to the positive side of the battery is what creates DC current.
What happens when a battery charges?
When A Battery Is Being Charged Charging is a process that reverses the electrochemical reaction. It converts the electrical energy of the charger into chemical energy. Remember, a battery does not store electricity; it stores the chemical energy necessary to produce electricity.
Why EMF is equal to terminal voltage?
Since V = emf − Ir, terminal voltage equals emf only if there is no current flowing. The internal resistance r can behave in complex ways. As noted, r increases as a battery is depleted.
Can the potential difference between the terminals of a battery ever be opposite in direction to EMF?
can potential difference between the terminal of the battery be ever be opposite in direction to emf? Yes. If you connect an external battery, with a greater emf, in a reverse direction (I mean, with opposite terminals), that may happen.
Is electromotive force the same as voltage?
One of the major difference between the EMF and voltage is that EMF is the energy supplied to the charge, whereas the voltage is the energy requires to move the unit charge from one point to another.
How do you calculate lost voltage?
Voltage is a measure of energy, and energy is always conserved. So the EMF of a cell is equal to the sum of its terminal potential difference, V t p d , and the lost volts, . This gives rise to the equation E = V t p d + V L This equation can be written in different forms, eg E = I ( R + r ) .