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What is the difference between gaussmeter and magnetometer?
Gauss meter_ Sensitive AC Gauss meters and EMF meters for measuring AC magnetic fields (50 Hz & 60 Hz Emf) Magnetometer- an instrument used for measuring magnetic forces, especially the earth's magnetism.
What is electrode potential and EMF of galvanic cell?
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.
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 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 applications of comparing Emf of two cells with the help of potentiometer?
I think you are talking about it's internal resistance or it's ability to supply a current to a load without significant drop in voltage. Experiment to find EMF of unknown cell The 1 Metre scaled potentiometer is placed across a cell of known EMF and the 'jockey' or slider connected to one terminal of a galvanometer. The second cell is wired with similar polarity to the first cell and connected from the other side of the galvo to the common negative terminal of the two cells. The slider of the potentiometer is progressively moved up from zero until the galvo shows no current. The EMF of the unknown cell is now a direct proportion to the reading in cm read of the metre scale. Example If the known cell has EMF of 3 volts and the galvo balances at 50cm then the unknown cell has EMF of1.5Volts Dry cells used in flashlights have a fairly high internal resistance whereas a Lead acid car cell has a very low internal resistance allowing the starter motor to draw hundreds of Amperes without volt drop.
What is the difference between gaussmeter and magnetometer?
Gauss meter_ Sensitive AC Gauss meters and EMF meters for measuring AC magnetic fields (50 Hz & 60 Hz Emf) Magnetometer- an instrument used for measuring magnetic forces, especially the earth's magnetism.
Which is preferred for measuring emf of a cell avoltmeter or potentiometer?
A voltmeter is used to measure voltage. A potentiometer is used to vary the amount of resistance in a circuit - it has nothing to do with measuring.
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....
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.
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.
Is free energy of cell reaction positive when emf of cell reaction is positive?
No, the free energy of a cell reaction is negative when the emf of the cell reaction is positive. This is because a positive emf indicates that the reaction is spontaneous and capable of performing work, resulting in a negative change in free energy.
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 silver and gold electrodes What is the emf of this cell?
1.03 V
How do you calculate total emf in series connecte cells?
With cells connected in series, the total emf of the 'stack' is simply the sum of the individual emf's of the individual cells. -- Even if one cell is connected backwards in the string. Then its emf is considered negative when the sum is being performed. -- All of this is true only as long as there is no external connection between the ends of the stack, you're measuring the emf on an 'open-circuit' basis with a voltmeter, and the cells are not providing any current to an external circuit. Once the series combination of cells is connected to an external circuit and begins to produce current, the total emf at the terminals of the stack will decrease. It'll depend on the magnitude of the current, and on the 'internal impedance' of each cell. If the cells are not precisely identical and in identical states of charge, then a calculation of the total emf is virtually impossible.
What is the Condition for terminal voltage across a secondary cell to be equal to its emf?
The condition for the terminal voltage across a secondary cell to be equal to its emf is when there is no current flowing through the cell. When there is no current, there is no voltage drop across the internal resistance of the cell, and thus the terminal voltage equals the emf.
What is the normal emf of a Weston cell at 20 degree Celsius and how does the emf change when the cell is used at 0 degree?
The normal electromotive force (emf) of a Weston cell at 20 degrees Celsius is approximately 1.018 volts. When the temperature drops to 0 degrees Celsius, the emf of the cell typically decreases slightly due to the reduced activity of the electrolyte and changes in the chemical reaction dynamics. This decrease is usually around 0.001 to 0.002 volts per degree Celsius. Thus, at 0 degrees Celsius, the emf would be lower than at 20 degrees Celsius.
What is electrode potential and EMF of galvanic cell?
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.
