0
Wiki User
∙ 11y ago
Add your answer:
Earn +20 pts
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 do you measure emf with a potentiometer not with voltmeter?
EMF (E''electromotive Force'') is another term for Volts, hence the E in electronic formulas and EMF is measured with a volt meter. A potentiometer is not a meter at all, it is a variable resistor
Can you measure the emf of a cell with a voltmeter?
you can, but you will not get accurate answer as voltmeter consumes some current. so, potentiometer is used instead to measure emf ---- the potentiometer must be set to the expected emf from the cell before you put the zero detector in circuit if its set too high it will charge the cell too low it will load the cell perhaps if you dont know the voltage of the cell before you measure it you should get a hi impedance voltmeter(electrometer) to set the potentiometer as close as you can manage before you connect the zero detector
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....
What is x y recorder and explain its working principle advantages disadvantages and applications?
Operating Principle: In x-y recorder, an emf plotted as a function of another emf, this is done by having 1 cell balancing potentiometer controlling the position of paper provided while another cell balancing potentiometer control the position of recording pen.
Explain the principle of null-method of measurement?
The null method is used in measuring the unknown EMF of batteries. The method is about using a potentiometer circuit with the battery of a known and then an unknown EMF connected to it one after the other and locating, in each case, the position of the 'null point'; the point on the potentiometer circuit where the current through the battery is zero.
Why emf of cell measurd by potentiometre is accurate?
The potentiometer is designed in such a way that no current is taken from the circuit you are measuring.
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.
What is the term for he phenomenon of emf development between two different metals placed in contact?
thermocouple effect
How do you measure EMF?
Use a voltmeter.
To measure EMF you would use a(n)?
"voltmeter"
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.
