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Why is the null reading necessary for the measurement of an emf?
Wiki User
∙ 12y ago
If I remember correctly the needle is connected to a spring and it moves according to the magnetic force produced by a coil connected to the emf. Due to use or mechanical handling, the needle at rest may not mark zero and may be rotated by a significant angle with no emf. You make the null reading to establish the zero of your measurement, so that you can compensate from deviation at rest.
You have a similar situation with a weight scale at home. Upon use, the zero at rest state may shift from its proper place, so before weighting yourself you need to adjust the needle position to read zero with no weight on it.
Hope this helps.
Wiki User
∙ 12y ago
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Unit of measurement for electromotive force?
emf has SI units of volts, equivalent to joules per coulomb.
Do all emf waves travel at the speed of light?
What is the range of the EMF spectrum
What happens to emf as a battery is used?
The emf of a batter as it is used will stay the same.
Is lenz law used to find induced EMF's?
It's primary usage is to determine the nature of an induced EMF from changes in the magnetic flux through a circuit. However, you must use Faraday's Law (and a unit conversion factor) to determine the SIZE of such an EMF.
Is it necessary to have cell in electric circuit?
A cell basically works as a producer of a potential difference in the circuit which is necessary for the electrons to travel in a region. Therefore using this principle we can understand that almost anything that can produce a PD can be used in an electric circuit. The best example would be of emf through EM induction of the Faraday's experiment
Who is responcible for performing necessary emf measurements?
who is responsible for coordinating emf surveys and measurement activities with command and supervisory personnel
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.
What is a another unit of measurement for an EMF?
a british band
Who is responsible for performing necessary emf measurements?
Bioenvironmental
Who is responsible for coordinating EMF surveys and measurement activities with command and supervisory personnel?
supervisors
Why does the total emf of dry cell in series not equal in the reading of voltmeter?
because in ckt connection there r done some ohmic loss due to the connecting wires and other factor , so voltmeter reading is not equal to its rated reading. and this also done due to different error like instrument error , measurement error etc...
Unit of measurement for electromotive force?
emf has SI units of volts, equivalent to joules per coulomb.
How are emf measured?
emf in volts
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....
Does motional emf call induced emf?
yes indused emf is also called motional emf. If an open coil is subjected to a variable magnetic field, at the ends of the coil a potential difference is induced which is called induced emf. If a coil is connected to an emf source and switched on, the rising current will produced an variable magnetic field which in turn produces an emf. It is called back emf.
When did EMF - band - end?
EMF - band - ended in 2009.
When was EMF - band - created?
EMF - band - was created in 1989.
