Most household appliances convert electrical energy to heat energy. There are certain applications in which intentionally creating heating losses is helpful. Joule heating isn’t always detrimental, but it can bring losses to the electrical system. Q = 5 2 x 20 x 10 = 5 kJ When Is Joule Heating Helpful? The heat energy generated in Joules can be calculated using Joule's heating formula: T is the time the current is allowed to flow in the circuit expressed in seconds.Ĭonsider an example of Joule heating, where 5 A of current is flowing through an electric wire of resistance 20 Ω for 10 s. R is the resistance offered by the circuit to the electric current flow in Ohms. Q is the amount of heat generated expressed in Joules. The Joule’s heating formula is given by: Q = I 2 Rt The law is named after the English physicist James Prescott Joule, who discovered that the amount of heat energy generated per second in a current-carrying conductor or circuit is proportional to the square of the circuit and the electrical resistance of the circuit. Joule’s heating formula is the mathematical equation governing the rate at which the electrical energy is converted into heat energy due to the resistance offered by the circuit. The rate at which the resistance converts electrical energy to heat energy can be calculated using Joule’s heating formula. The resistance is an important property determining the current flow through a circuit. Joule heating is also known as Ohmic heating or resistive heating. In the Joule heating process, depending on the circuit conditions, some portion of electrical energy is converted into heat as electric current flows through the circuit of finite conductivity. In general, Joule heating can be described as the physical effect that increases the internal energy and collision of electrons in a circuit carrying current, resulting in the generation of heat energy. The efficiency of the circuit is compromised to be less than 100% with heating losses. The output power will always be less than the input power in the presence of heating losses. A portion of the electrical input power is lost in the form of heat energy. The electrons colliding with each other dissipate energy in the form of heat and generate power loss. When current flows through a circuit or a conducting material, the resistance associated with the circuit or material causes a collision of electrons. We already know that the flow of electrons in a closed circuit is electric current. This article explores Joule heating in electric circuits and how to calculate the energy lost in the form of heat. It is the heating loss or Joule heating phenomenon that limits the application of incandescent lamps when trying to save power. The resistance offered by the filament to the flow of electric current produces heat energy, which can be calculated using Joule’s heating formula. Power loss due to heating is the main drawback of incandescent lamps, diminishing their efficiency. As part of this transition, incandescent lamps are being discarded. We are in the process of transitioning into more efficient lighting, and it is safe to say it is the era of LED lighting systems. Power loss due to heating is the main drawback preventing the use of incandescent lamps The Joule’s heating formula is given by Q=I2Rt.Īccording to Joule’s heating formula, the heat energy generated is proportional to the time when the electric current and electrical resistance are constant. Joule heating is the physical effect that increases the internal energy and collision of electrons in a circuit carrying current that results in the generation of heat energy.
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