The potential at the cathode of the source will be higher than the potential at the anode. When a potential difference or the voltage is developed across the passive elements is known as the voltage drop. Passive elements-the electrical elements that do not generate power , such as resistors, capacitors, etc. The voltage developed is a result of the electric field. Now the major emf and voltage difference is, voltage or terminal voltage is too small in comparison with the emf.
It implies that the Intensity of Emf developed will be always greater than the voltage as the voltage exists in a loaded circuit. Due to external resistance, there is always voltage drop or energy loss which will lead to varying intensity. But, emf is always constant. Let us look at other voltage and EMF difference as listed below:.
Emf is the voltage developed between two terminals of a battery or source, in the absence of electric current. Voltage is the potential difference developed between the two electrode potentials of a battery under any conditions. It is the potential difference between the two terminals of a battery or cell in an open circuit. Emf is an open circuit voltage.
It is the potential difference between the two terminals of a battery or cell in a closed circuit. Terminal voltage is a closed-circuit voltage. Emf is independent of the resistance of the electrical circuit but is dependent upon the internal resistance of the circuit. It is directly proportional to the resistance between the two terminals. The formula used to calculate emf is given by:. R- External resistance of the electrical circuit.
I- Current flowing through the circuit. EMF of any circuit can be measured by using a potentiometer. The voltage developed in an electric circuit is measured by using a Voltmeter. Electromotive force EMF is equal to the terminal potential difference when no current flows. EMF and terminal potential difference V are both measured in volts, however they are not the same thing.
Next Steps. The EMF of the cell can be determined by measuring the voltage across the cell using a voltmeter and the current in the circuit using an ammeter for various resistances. We can then set up a circuit to determine EMF as shown below. Investigating EMF. Also it is used in the electric generators and motors such as hydroelectric dams, which produce the electricity that is now integral to our modern technological needs.
A current research project at Birmingham, MAG-DRIVE, is finding ways to develop and improve permanent magnet materials that can be used in the next generation of electric vehicles. EMF is also generated from solar cells so it is important in renewable energy research topics. The voltage is caused by the electric and the magnetic field. The voltage is developed between the ends i. The potential of the positive endpoint of the source is higher as compared to the negative points.
When the voltage develops across the passive element, then it is called the voltage drops. The energy supply from the source to each coulomb of charge is known as the EMF. In other words, it is the energy supply by some active source such as the battery to the unit coulomb charge.
The EMF stands for the electromotive force. The electromotive force of the above circuit is represented by the formula Where, r — internal resistance of the circuit. R — External resistane of the circuit.
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