How Does the Heating Effect of Electric Current Work in Daily Life?
The heating effect of current is used widely by all of us in our day-to-day life. The kettle, heater, toaster, electric iron, etc. are used by all of us as alternatives to the conventional methods when it comes to cooking and laundry. The same heating effect is used in the electric bulbs which make for the alternative of the conventional lamps. All these devices have revolutionized the world that we live in over the past years. In this section today, we will learn about the heating effect of electric current definition and the application of the heating effect of current.
Whenever an electric current gets passed through the conductor, it tends to generate heat because of the hindrance that is caused due to the conductor to the current flowing inside. The amount of work done to overcome this hindrance to the electric current produces heat in that specific conductor.
Heating Effect of Electric Current Formula
Let us now learn about the formula of the heating effect of electric current.
When the current flows through the conductor, thermal energy gets generated inside the conductor. This heating effect of the current is dependent on three different factors.
The resistance of the conductor: The higher the resistance, the more heat is generated.
The time duration of the current flow: If the current flows for a longer time, the amount of heat generated is higher.
The higher the flow of the electric current, the higher is the generation of heat.
Therefore, the heating effect generated by the current I, through the conductor having resistance R, for the given time T, is given by the following equation.
H = I2RT
This equation is also known as Joule’s equation of electrical heating.
Application of Heating Effect of Electric Current
At the point when an electric flow moves through a conveyor, it creates heat due to the conductor's impedance to the flowing current. Heat is generated in the conductor as a result of the work done to overcome the impediment to the current.
Application: The following gadgets use the heating effect of electricity for various purposes:
Electric Iron
Mica is an encasing that is set between the metal component of iron and the coil. The passage of current heats the coil, which is subsequently transmitted to the metallic component through mica. Finally, the metal component is heated and utilised for ironing garments.
Electric Heater
A coil made of high resistance nichrome wire is used in an electric heater. The coil is coiled around grooves formed of ceramic or china clay. When current travels through the coil, it heats up, which is then utilised to heat cooking containers.
Electric Fuse
When there is a rapid increase in current in any electrical instrument, the device burns down, which can result in a fire. To avoid this sort of mishap, a conducting wire with a low melting point is connected in series with the circuit. When the current increases, the wire melts due to overheating, causing the electrical circuit to break.
Water Heater and Electric Heater
When these items are connected to an electrical source, they grow hot, but the cables stay cool. They are made of nichrome, which has a high resistivity and hence a high resistance. The amount of heat produced is related to the resistance of the substance through which the current travels.
Electric Bulb
An electric bulb's filament is made of tungsten, which has a high melting point. A filament is contained within a glass envelope filled with nitrogen and argon gas. Because the resistance of the tiny filament is quite high, the quantity of heat produced is significant, as is the electric current flowing through the filament. The filament bulb gets white hot due to the high quantity of heat produced. As a result, the filament of the bulb releases light and heat.
The Electric Fuse
When a strong electric current is sent through wires made of certain materials, they quickly melt and shatter. These wires are utilised in the manufacture of electric fuses. Electrical fuses are used in all electrical circuits in all structures. There is a maximum current that may safely flow through a circuit. If the current accidentally exceeds this limit, the wires may overheat and catch fire. If there is a suitable fuse in the circuit, it will blow and break the circuit.
According to Joule's law, the quantity of heat produced in a conductor is:
It is relative to the square of the electric current passing through it.
It is exactly proportional to the conductor's resistance.
The time it takes for an electric current to pass through a conductor is directly proportional to the time it takes for the current to flow through the conductor.
Kirchoff’s First Law
The total of electric currents entering and exiting a junction equals the amount of currents leaving the junction. Kirchhoff's First Law follows naturally from the conservation of electric charge. The total of the currents is zero if the currents entering the junction are positive and the currents exiting the junction are negative.
\[\Sigma I=0\]
\[(\Sigma I =0 \Rightarrow I1+I2 = I3 + I4 + I5)\]
Kirchhoff's Second Law
In a DC circuit, the total of electric potential differences along every closed loop is zero. Kirchhoff's Second Law is a result of energy conservation. The change in electric potential energy per unit charge is equal to the change in electric potential energy. The total of the changes in electric potentials along any closed loop in a dc circuit is zero if the electric potential is negative in the direction of electric current and the rise in potential is positive.
\[\Sigma V \] =0
FAQs on Heating Effect of Electric Current: Definition, Formula & Applications
1. What is the heating effect of electric current?
The heating effect of electric current is the phenomenon where a conductor produces heat when an electric current passes through it. This occurs because the conductor offers resistance to the flow of current. The work done by the electrical energy to overcome this resistance is converted into thermal energy, causing the conductor's temperature to rise.
2. What is Joule's Law of Heating and what is its formula?
Joule's Law of Heating states that the heat (H) produced in a conductor is directly proportional to the square of the current (I), the resistance of the conductor (R), and the time (t) for which the current flows. The formula is expressed as:
H = I²Rt
Where:
- H is the amount of heat produced (in Joules).
- I is the electric current (in Amperes).
- R is the electrical resistance (in Ohms).
- t is the time duration (in seconds).
3. What are some practical examples of the heating effect of current in daily life?
The heating effect of electric current is used in many household appliances. Some common examples include:
- Electric Heaters and Geysers: These use a high-resistance coil (like nichrome) to generate a large amount of heat to warm a room or water.
- Electric Iron: A coil inside the iron heats up, which in turn heats the flat metal base used for pressing clothes.
- Incandescent Bulbs: The filament, made of tungsten, gets heated to a very high temperature until it glows and produces light.
- Electric Fuse: A safety device with a wire of low melting point that melts and breaks the circuit if the current exceeds a safe level, preventing damage to appliances.
4. Why exactly do conducting wires get hot when electricity passes through them?
Conducting wires get hot due to collisions at the atomic level. While conductors allow electrons to flow, they still possess some resistance. As a stream of electrons (the electric current) moves through the wire, they collide with the fixed atoms and ions of the conductor material. Each collision transfers kinetic energy from the electrons to the atoms, causing them to vibrate more vigorously. This increased atomic vibration is what we perceive as heat.
5. How does the resistance of a conductor influence the amount of heat it produces?
The resistance of a conductor is a crucial factor in heat production. According to Joule's Law (H = I²Rt), the heat produced is directly proportional to the resistance (R). This means for the same amount of current and time, a conductor with higher resistance will generate more heat. This is because higher resistance implies more frequent and intense collisions between electrons and atoms, leading to a greater conversion of electrical energy into thermal energy. This is why heating elements are made from high-resistance materials like nichrome, not low-resistance materials like copper.
6. What is the difference between the material used for a fuse wire and a heating element in an appliance?
The primary difference lies in their purpose, which dictates their material properties, specifically their melting points.
- A heating element (e.g., in a toaster) is made of a material with high resistivity and a very high melting point (like nichrome). The goal is to produce a lot of heat continuously without melting or breaking.
- A fuse wire is made of an alloy with high resistivity but a very low melting point (like a tin-lead alloy). Its purpose is to heat up and melt quickly to break the circuit when the current becomes dangerously high, thus acting as a safety device.
7. Is the heating effect of current always a useful phenomenon?
No, the heating effect is not always useful. While it is intentionally used in devices like heaters and irons, it is often an undesirable side effect. The most significant disadvantage is the loss of energy in power transmission. A considerable amount of electrical energy is converted into heat and lost to the surroundings as electricity travels through long transmission lines from power stations to homes. This reduces the overall efficiency of the electrical grid and also affects the performance of sensitive electronic devices like computers, which require cooling systems to dissipate unwanted heat.
8. Who discovered the heating effect of electric current?
The heating effect of electric current was discovered by the English physicist James Prescott Joule in the 1840s. Through his experiments, he established the relationship between the heat generated, the current flowing, the resistance, and time. The fundamental law describing this phenomenon, Joule's Law of Heating, is named in his honour.
