Electrical Heating: Understanding the Joule Heating Effect
by Yuvi K - December 17, 2023
What is the Joule Heating Effect?
The Joule heating effect is a phenomenon that applies to the transfer of electric current through certain materials. This phenomena results in the heating of the material, due to the conversion of electrical energy to thermal energy. This process is also referred to as the ohmic heating or resistive heating as it involves the transfer of energy through electrical resistance.
Working of the Joule Heating Effect
This happens as soon as the current starts to move along a path, for example, an electrical wire, and meets with some resistance. When this happens, power will begin to dissipate in the form of heat, and it is this dissipated energy, which causes the wire to heat up, and this is the Joule heating effect.
In order for the Joule heating effect to take place, three things need to happen. First, there must be a complete, unbroken circuit. This circuit must have an electrical power source, like a battery, and the wire through which the current will travel must have some resistance. Lastly, the electric current must flow through the circuit and encounter the resistance.
How does Joule Heating Affect Your Life?
The Joule heating effect is present in our everyday lives and is an integral part of many of our electrical appliances. It is the main reason why our electric irons, water heaters and cooktops get hot and how our electric stoves, toasters and coffee makers are able to cook our food. It also explains why the coils in our hairdryers, straightening irons and curling irons get hot when in use. The Joule heating effect is also the reason the mica strip heaters used in electric furnaces are able to emit heat.
Formula of Joule Heating Effect
The amount of heat produced by the Joule heating effect can be described by the following formula:
In this equation:
- Voltage (in volts) is the electric potential delivered by the power source.
- Current (in amps) is the amount of electricity moving through the circuit.
- Resistance (in ohms) is the opposition to the flow of electrons through the circuit.
- Time (in seconds) is the amount of time the current is flowing through the circuit.
Joule Heating Example 500 to 800 Words
An example of the Joule heating effect in action would be water being heated in an electric kettle. In a kettle, an element is heated when electricity passes through it, and this electric current is resisted by the element, thereby causing it to heat up. This process of resistance heating is known as the Joule heating effect.
Let’s take a look at the physics behind this process. The element that the electric current flows through is a wire and wires all have resistance. This resistance, as explained above, is what leads to the conversion of electrical energy to heat energy, through the Joule heating effect.
As water heats up, it changes from a liquid to a gas and as this occurs energy must be released. This energy is responsible for the movement of the molecules contained within the water. The Joule heating effect supplies the energy that is necessary for this process to occur.
As soon as the electricity begins to flow, the transfer of energy takes place and the element begins to heat up. As the element warms up, so does the water that has come into contact with it and begins to boil.
To summarise, the Joule heating effect occurs when electric current encounters resistance and causes the wire to heat up, which then transfers this heat energy to the item it comes into contact with. The Joule heating effect is present in our everyday lives and is responsible for the ability of many of our electrical appliances to work.
Conclusion
To conclude, when electric current passes through a material with resistance, it heats up. This is known as the Joule heating effect and it underpins the functioning of many of the electrical appliances we use in our daily life.
