Difference between emf and potential difference class 12

EMF is the work done by the cell in moving a coulomb of charge across its terminals. It represents the energy transferred per coulomb to the charges. Some of this energy is lost as heat due to internal energy. Hence the net energy gained by the charge = the emf - heat lost. This net energy gained per coulomb is called the terminal voltage. This is the voltage across the ends of the battery. Created by Mahesh Shenoy. The internal resistance does indeed impede the speed (wow, it sounds like assonance XD ) of the current carrying charge, but since the negative terminal does the work to PUSH the charge against such resistance as well as the repulsion by terminals, providing the charge enough energy, such that it restores its initial speed and no decrease in speed is visible. and hence due to all this hard work the heat is evolved. Its just like, when your car gets stuck between large rocks or in a swamp, you apply all the force you can probably by hitting that accelerator.... and as you persistently try to get out it, your engine has heated up a good deal. So its kind of analogous to our case, where we try to get over the obstacles and in the process we end up dissipating heat, which is an indication that work is being done against an external force. There is this IDEA of current flow that the scientists and researchers have been following since the earliest of times and hence, we too have come to accept it as the CONVENTION. This convention created, is to assume the flow of p...

While working with batteries and cells in real life, we experience two different potential differences between the terminals of the battery. These potential differences are due to the non-ideal nature of the battery which increases the resistance inside the battery. The potentiometer is used to measure such differences. These different values are called e.m.f and the potential difference of a cell. To understand why this phenomenon occurs, we need to look at the resistance offered by the circuit and the battery. Let’s look at these concepts in detail. Electromotive Force (E.M.F) of a Cell The energy delivered to the unit charge by a cell is known as the electromotive force EMF. The batteries are available in a variety of forms and sizes. There are numerous distinct types of generators that are powered by various sources. All these devices irrespective of what their energy sources are, create potential differences across their terminals and can supply current if resistance is connected to them. It is known that potential difference creates an electric field that causes charges to move and that in turn creates current. Thus, this potential difference is sometimes also referred to as electromotive force (emf). Its unit is considered to be all Volts(V). Even though EMF is directly related to the potential difference produced by the voltage source, but it still differs from the actual potential difference that is reflected on the terminals of the battery. The terminal voltage a...

Last updated on December 13th, 2022 at 03:55 pm Let’s solve 2 numerical problems based on Numerical problems based on emf and potential difference 1] If the emf of a battery is 9 V, how much energy is converted from chemical to electrical when 2 C of charge flow? 2] What is the p.d. across a resistor if 24 J of heat is produced when a current of 2 A flows through it for 10 s? Solutions 1 ] solution: emf = energy converted from chemical to electrical per unit charge. So energy converted = Vq = 2 x 9 J = 18 J 2] solution: 2 A current flows for 10 s. Hence, Charge Q = current x time of flow = 2 x 10 C = 20 C of charge. Potential difference(V) = W/Q = work done per unit charge = energy per unit charge = 24/20 V = 1.2 V [ Related Posts: • State the difference between emf and potential difference with the energy view • Electrical Potential difference & mechanical work - numerical problems • How to define Voltages, Electromotive Force (emf), and Potential Difference (PD)? • Potential difference (Electrical) worksheet - with solved numerical • Numerical problems on electric potential energy • Derive the Formula of Electric Potential Difference from the energy difference in… • State the difference between emf and potential difference with the energy view • Electrical Potential difference & mechanical work - numerical problems • How to define Voltages, Electromotive Force (emf), and Potential Difference (PD)? • Potential difference (Electrical) worksheet - with solved numerical • Nu...

A battery is a component in the electrical circuit that transforms energy from a non-electrical form. It converts chemical reactions into electrical energy. The circuit is completed when the electrons travel through wires from the terminals of a battery to the device. EMF is a measure of an electric current’s electromotive force (a measure of actual output voltage). It occurs when the voltage of the electric current changes. Potential Difference occurs when two points in space have different concentrations of charge or when two points in space have different velocities and consequently different electric fields but are otherwise identical. Actual Output Voltage The actual output voltage is the difference between the highest and lowest voltages on a power source. While you can find both positive and negative output voltages, most power sources only have one voltage in use at any given time. An output is a single value used to represent any voltage on the power source. Even if the voltages change among the various output components, you can still get a single number for a given output. When multiple voltages are used for different components inside a single output, you will still see two numbers (the two highest and two lowest) as you saw when looking at how much actual output voltage is in the battery. This enables one to look at a particular combination of all the voltages in the output. Terminals of a Battery To understand why we chose to name the terminals of a battery “...