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Electrode potential refers to the voltage developed at an electrode when it is immersed in an electrolyte solution, reflecting its tendency to gain or lose electrons. In a galvanic cell, the electromotive force (EMF) is the overall voltage generated by the cell, which is the difference between the electrode potentials of the two half-cells (anode and cathode). The EMF indicates the cell's ability to drive an electrochemical reaction and can be measured under standard conditions. A higher EMF implies a greater tendency for the cell to produce electrical energy.
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What provides a voltage difference in a cell?
Voltage is the colloquial term. Actually the word potential difference is to be used. More over emf is another term to be used. Emf is the pd of a cell when it is not placed in a closed circuit or the cell does not deliver any current. As the cell delivers the current then emf will be reduced by an amount of pd across the internal resistance of the cell.Here emf is by chemical energy converted into electrical formSame emf can also be produced by using magnetic flux or heat energy and even mechanical energy.If we use magnetic flux then it is known as electromagnetic inductionAs we use heat, then it is termed as thermo emfEven mechanical energy gives out emf in case of crystals. This is known as piezo electricityAlso as we make a circuit with a cell, resistance and a switch and as we switch on then current flows through resistance and a potential drop is produced across the resistance given by the expression V = i RThis is also known as the voltage drop across the resistor.AnswerVoltage, or potential difference, is created by charge separation which, as the previous answer indicates, can be achieved in numerous ways. A simple chemical cell or battery, for example, separates charge chemically, causing an imbalance in the quantity of electrons in and, therefore, the charges on, its two electrodes. As a result, one electrode has a higher potential than the other, so there is a potential difference between the two.
What is the cell potential?
Cell potential, also known as electromotive force (EMF), is the measure of the driving force behind the flow of electrons in an electrochemical cell. It is the difference in electric potential between two electrodes in a cell and is a measure of the cell's ability to produce an electric current. The cell potential is a key factor in determining the feasibility and direction of redox reactions in a cell.
Why cant you use voltmeter 2 calculate emf of a cell?
A voltmeter measures potential difference across a component, which may not necessarily be equal to the EMF of a cell due to internal resistance in the cell and voltage drops across other components in the circuit. To accurately measure the EMF of a cell, a potentiometer or a high-resistance voltmeter is used in conjunction with a null point method.
Why the unit of emf is not 'newton'?
The unit of electromotive force (emf) is not 'newton' because emf measures electric potential difference, while newton is a unit of force. Emf is expressed in volts (V), which corresponds to joules per coulomb (J/C), indicating energy per unit charge. The different physical quantities—electric potential versus force—require distinct units to accurately represent their respective properties in physics.
Why emf falls even when the cell is not in use?
When a cell is not in use, there can still be a small amount of current flowing through it due to internal factors like self-discharge or leakage currents. This internal current can lead to a drop in the cell's electromotive force (EMF) over time, even when the cell is not actively powering a device.
What are the differences between galvanic series and emf series?
1)galvanic series is for both elements and alloys whereas emf series is only for elements 2)galvanic series tells about relative tendencies of corrosion whereas emf series tells about relative tendencies of displacement
Can the potential difference across a battery be greater than its EMF?
If the emf of a battery is E Volt, the potential difference across a battery is given byV = 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.=====================================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.======================================...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 theCombined 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
A voltaic cell is made of copper and aluminum electrodes What is the emf of this cell?
The EMF of a copper-aluminum voltaic cell can be determined by the standard reduction potential of each metal. Copper has a higher standard reduction potential than aluminum, so the cell will have a positive EMF. The exact value can be determined by calculating the difference between the reduction potentials of copper and aluminum.
Explain the theory behind the potentiometric titration of acid base?
In potentiometric titration, the change in the concentration of H+ ions are monitored based on the emf measurement with respect to Saturated calomel electrode ( a reference electrode having a standard reduction potential of 0.2422 V). H+ ions concentration in terms of pH change is measured using primarily by quinhydrone electrode. Based on hydrogen electrode also it can be measured. An electrochemical cell consists of H+ ions (acid to be titrated) in contact with hydrogen gas (1 atm) or quinhydrone/ quinone should be formed and the emf (potential difference) of the cell is measured with reference to saturated calomel electrode (SCE). Then based on Nernst equation value of standard electrode potential of hydrogen ion is, EH = Eo + 0.0591 log [H+] or EH = - 0.0591 pH since Eo = 0 V and -log [H+] = pH So EMF of the cell is Ecell = ESCE - EH Ecell = 0.2422 - EH The Ecell value is plotted ( Y axis) against volume of base added (X axis). The volume corresponds to drastic Ecell change gives equivalence point of the titration. At equivalence point all the free H+ ions are replaced as H2O and this is reflected and can be inferred in the Ecell values.
Is potential difference always less than emf of the cell?
No. Because during charging process of a battery current flows in opposite direction to the discharging/consumption. so equation Emf=P.d. +Ir is changed to Emf=p.d. +Ir. Hence during charging process of a battery Potential difference is greater than electromotive force.
Why emf of battery driving potentiometer is greater than emf of the cell to be measured?
Bcoz the emf which is to be measured is less than emf of driving cell....
How do you determine the emf and internal resistance of a cell?
You can measure the emf of a cell by using a voltmeter, as this draws current from a cell. You can use the voltage, the emf, and the load resistance to determine the internal resistance of the cell.
Which devices has a source of emf inside it?
Electro Motive Force, is the potential to make electricity.A battery is a source of EMF and so is an electrical generator, or any moving magnetic field around a conductor.A solar cell is also a source of EMF.
What provides a voltage difference in a cell?
Voltage is the colloquial term. Actually the word potential difference is to be used. More over emf is another term to be used. Emf is the pd of a cell when it is not placed in a closed circuit or the cell does not deliver any current. As the cell delivers the current then emf will be reduced by an amount of pd across the internal resistance of the cell.Here emf is by chemical energy converted into electrical formSame emf can also be produced by using magnetic flux or heat energy and even mechanical energy.If we use magnetic flux then it is known as electromagnetic inductionAs we use heat, then it is termed as thermo emfEven mechanical energy gives out emf in case of crystals. This is known as piezo electricityAlso as we make a circuit with a cell, resistance and a switch and as we switch on then current flows through resistance and a potential drop is produced across the resistance given by the expression V = i RThis is also known as the voltage drop across the resistor.AnswerVoltage, or potential difference, is created by charge separation which, as the previous answer indicates, can be achieved in numerous ways. A simple chemical cell or battery, for example, separates charge chemically, causing an imbalance in the quantity of electrons in and, therefore, the charges on, its two electrodes. As a result, one electrode has a higher potential than the other, so there is a potential difference between the two.
Why emf of cell measurd by potentiometre is accurate?
The electromotive force (emf) of a cell measured by a potentiometer is accurate because a potentiometer measures the potential difference between the two electrodes without drawing any current from the cell, leading to minimal disturbance in the cell's internal resistance. This allows for a more precise measurement of the emf of the cell under open circuit conditions.
What is the cell potential?
Cell potential, also known as electromotive force (EMF), is the measure of the driving force behind the flow of electrons in an electrochemical cell. It is the difference in electric potential between two electrodes in a cell and is a measure of the cell's ability to produce an electric current. The cell potential is a key factor in determining the feasibility and direction of redox reactions in a cell.
Why cant you use voltmeter 2 calculate emf of a cell?
A voltmeter measures potential difference across a component, which may not necessarily be equal to the EMF of a cell due to internal resistance in the cell and voltage drops across other components in the circuit. To accurately measure the EMF of a cell, a potentiometer or a high-resistance voltmeter is used in conjunction with a null point method.
