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If the emf of a battery is E Volt, the potential difference across a battery is given by
V = E -I r where I is the current in the circuit and r is the inetrnal resistance.
Hence E and V will be equal only when I = 0.
The maximum potential difference across the battery will be equal to E only if I = 0.
In gnereral potential difference can be equal or less than the emf.
E.m.f can never exceed the potential difference.
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A battery charger is a device used to put energy into a secondary cell or (rechargeable) batteryby forcing an electric current through it.
Hence to charge a battery another source of emf is needed.
The combined emf is now will be (E - E1) where E is the emf of the battey in quesiton and E 1 is the emf of the external source used to charge the battery.
Note that E-E1 will be negative in sign.
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A battery is charged only when its emf is less than its maximum emf.
Suppose that the maximum emf of a cell is 1.5V. The battery should be charged only when its emf is less than 1.5 V say 0.5 V.
To charge the cell we use a different source of emf E1 say 3V.
The positive of the second source is connected to the negative of the cell so that the
Combined emf is now 0.5 - 3 = -2.5V.
The negative sign indicates that the emf is opposite to the emf of the cell which is 0.5V.
Since the cell is getting charged, the difference in emf is gradually reduced to zero when the cell is fully charged.
In modern charging units there are provisions so that the cell is never allowed to be over charged, even if the charging unit is in on for about 12 hours.
When the cell is fully charged, (that is when the emf of the cell is now 1.5V), the potential difference between either the second source or cell will be zero.
Taking into consideration the sign of the emf and the direction of current through the cell and the sign of the potential difference, the potential difference will be always less than the emf of the cell (which gradually increases while charging).
Note that the potential difference is negative if the emf of the cell is taken as positive.
Also note that the cell is charged only when its emf is less than its maximum e.m.f
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Is potential difference directly or inversely proportional to resistance?
Potential difference is directly proportional to resistance according to Ohm's Law. This means that as resistance increases, the potential difference across a component also increases, assuming the current remains constant.
Can terminal potential difference be greater than the emf supplied?
No, the terminal potential difference cannot be greater than the emf supplied. The emf represents the maximum potential difference that the cell or battery can provide, while the terminal potential difference is the actual potential difference across the terminals when a load is connected.
What are the differences between potential difference and emf?
Potential difference is the difference in electric potential energy between two points in a circuit, while electromotive force (emf) is the total energy provided per unit charge by a battery or voltage source. In other words, potential difference measures the voltage drop across a component in a circuit, while emf represents the energy per unit charge supplied by the source.
Is potential difference always less than emf of the cell?
Yes, potential difference across a cell is typically less than the electromotive force (emf) of the cell due to internal resistance and other factors affecting the flow of electric current. The emf represents the maximum voltage a cell can provide, while the potential difference takes into account the voltage drop caused by these internal resistances.
What is the potential difference in electricity?
Potential difference, also known as voltage, is the force that drives the flow of electric current in a circuit. It is measured in volts and represents the energy per unit charge available to a charge to move in an electric field. A higher potential difference leads to a greater flow of current in a circuit.
What is the potential difference across the terminals of a battery?
Please share your answer?
Is potential difference directly or inversely proportional to resistance?
Potential difference is directly proportional to resistance according to Ohm's Law. This means that as resistance increases, the potential difference across a component also increases, assuming the current remains constant.
Can terminal potential difference be greater than the emf supplied?
No, the terminal potential difference cannot be greater than the emf supplied. The emf represents the maximum potential difference that the cell or battery can provide, while the terminal potential difference is the actual potential difference across the terminals when a load is connected.
What are the differences between potential difference and emf?
Potential difference is the difference in electric potential energy between two points in a circuit, while electromotive force (emf) is the total energy provided per unit charge by a battery or voltage source. In other words, potential difference measures the voltage drop across a component in a circuit, while emf represents the energy per unit charge supplied by the source.
Why does a battery work?
A battery s a source of constant potential difference , this potential difference drives the electrons present in the wire and this constitutes current .Shortly the potential difference across the battery terminals does work on the conduction electrons present inside the conductor. Actually a battery is an electrolytic device ,after some time the electrolyte completely exhausts this state of battery is called as discharged state.
How is the potential difference maintained across the end of the conductor?
That's the job of the battery or other power supply.
What is terminal PD?
A terminal potential difference is the potential difference appearing across the terminals of a voltage source, such as a battery or a generator, which varies according to the load supplied.When the battery or generator is off load (i.e. no load is connected to it), the terminal potential difference is equal to the electromotive force of that battery or generator.The terminal potential difference tends to decrease as the load current increases, due to a corresponding increase in the internal voltage drop of the battery or generator.
Under what circumstances can the terminal potential difference of a battery exceed its emf?
"The potential difference between the terminals of a battery will equal the emf of the battery when there is no current in the battery. At this time, the current though, and hence the potential drop across the internal resistance is zero. This only happens when there is no load placed on the battery-that includes measuring the potential difference with a voltmeter! The terminal voltage will exceed the emf of the battery when current is driven backward through the battery, in at its positive terminal and out at its negative terminal." Raheel Ahmed Quaid i Azam University Islamabd Physics Dept
A step-down transformer has 525 turns in its secondary and 12500 turns in its primary If the potential difference across the primary is 3510 V what is the potential difference across the secondary?
The potential difference across the secondary coil will be 147.42 Volts
What is the PD across two resistors connected parallel to a battery of emf 6V?
The potential difference across two resistors connected in parallel to a battery with a potential difference of 6 volts is 6 volts. Kirchoff's Voltage Law: The signed sum of the voltage drops in a series circuit is zero. This means that that the two series circuits involving the battery and each resistor have the same voltage across each other, and the series circuit involving the two resistors have the same voltage across each other.
Name a device that helps to maintain a potential difference across a conductor?
volt meter is the device that helps to maintain a potential difference across a conductor
What is the potential difference across a single 4 Ohm resistor if the source voltage is 230v?
the potential difference across the single 4ohm resistor is 230volts.
