To understand the difference between emf and voltage, we must understand that emf means electric force and refers to the voltage present at the source ends in the absence of current and the presence of voltage at the source ends when the circuit is closed to conduct electricity.
The received voltage is very small compared to the emf and is due to the internal resistance of the source causing the voltage to decrease.
EMFs are caused by charged particles as a result of the separation of electrons from atoms using certain types of energy such as chemical, mechanical, light.
Voltage is the difference between the electrical states on the poles. In a closed electrical circuit, electrons move from the negative region to the positive region. Electric voltage is defined as the work done by an electric force to transfer a charge from one point in the field to another
What is EMF?
EMF stands for electromagnetic force. EMF is the voltage at the ends of a source in the absence of current. EMF theory describes the amount of work required to separate the charge carriers in the source current, such that the force acting on the charge at the ends of the source is not a direct result of the Emf field developed as a result of internal repulsion.
Electromagnetic Force (EMF) is defined as – the amount of work done in converting energy and the amount of current passing through a power source or generator. EMF is measured in Volts and is denoted by the symbol ε (or E).
EMF= A/Q (where A= amount of work performed and Q= amount of electricity)
What is Voltage?
Voltage is defined as the energy required to move from one end of the charge unit to the other. Voltage is measured in volts and is indicated by the symbol V.
Voltage is mostly developed between two poles of an electric circuit, ie. between the anode and cathode of the battery.
The positive end of the battery is known as the cathode and the negative end of the battery is known as the anode. The potential at the cathode of the source will be greater than the potential at the anode.
When a voltage or potential difference develops in passive materials, it is known as a voltage drop. (Passive elements-electrical elements that do not produce power, such as resistors, capacitors, etc. used to dissipate, store charge).
Difference Between EMF and Voltage
| EMF | Voltage |
| It denotes the voltage produced inside the electric source. | It is the difference potential difference between two points |
| External forces work in moving a charge from one pole to another pole inside a source | It is the work in moving a charge from one pole to another through a wire |
| E = I * (R + r) | V = I * R |
| It follows the coulomb force operation | It follows a non-coulomb force operation |
| It measured with EMF meter | It is measured with a voltmeter |
| It is always greater than the voltage | It is always lesser than EMF |
| Its intensity is constant | Its intensity is not constant |
| EMF is caused in a gravitational, electric or magnetic field | Voltage is caused only in the electric field |
