emf and voltage
AnswerElectromotive force is the potential difference created by a source, such as a battery or generator, when it is not connected to a load -in other words, on 'open circuit'.
Voltage drop is the potential difference across a load, such as a resistor, which causes current to flow through that load.
A voltage drop occurs, internally, in batteries and generators, when they are supplying a load. The battery or generator's terminal voltage, when supplying a load, is its e.m.f. less its internal voltage drop.
As the load current increases the losses in the circuit increases (I2R loss) and speed of the generator decreases so the voltage falls a little. and this voltage fall can be adjusted by increasing the speed of the generator and Iron losses are taken as constant losses.
EMF is the voltage across a coil (or motor) due to changes in the magnetic field. If you change the current the coil will generate a voltage (in the opposite direction of the current). So it is not the field but the change that matters.
it doesn't develop emf ..........
145.25 v
(i) EMF (Electro Motive Force) the source of voltage can increase or decrease voltage. (ii) Load connected can increase or decrease voltage (In case of overload voltage reduces.) (iii) Resistance of wire - I R loss ( Voltage drop V = IR)
Voltage drop is resultant of IR ie current and the line resistance, not dependent on impressed emf
Voltage drop
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
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.
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.
There is analogy between pressure and EMF or voltage. What pressure is to the liquids, EMF or voltage is to electric current. But, of course, they are not the same.
An induced electromotive force (emf) is an induced voltage. Voltage (emf) causes current flow, and this induced voltage will cause a current that is called the induced current.We might also add that the induced current will cause a magnetic field to expand about the current path, and this field will "sweep" the conductor. The sweeping of the conductor by that expanding magnetic field will set up an emf that will oppose the emf that was creating it.CommentTechnically, there is no such thing as an 'induced current'. It is voltage that is induced. Any current flows as a result of that induced voltage being applied to a load. But that current is certainly NOT induced!
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.
EMF (short for "electromotive force" - not a well-chosen name, since it isn't exactly a force) is more properly called a "voltage". A device that provides that can be a battery, or you can get the voltage from the outlets in your home.
the voltage of a battery could be larger than the emf if you are to charge the battery, in that case V=E+Ir .
EMF is electromotive force. It is another name for voltage. Voltage is electric potential in joules per coulomb. Current is electric flow, in amperes. Amperes are coulombs per second. Voltage and current are not the same thing, and "emf current", or "voltage current" does not make sense.
"Potential difference" or "Voltage".