Heating Effect Electric Current - Detailed Guide

We will discuss in this article the Heating effect of electric current or what is heating effect of current, what are the effects of heating effects, the Heating effect of class 10, and the heating effect of class 7

• Heating effect of electric current: What is the heating effect of electric current? Explain the heating effect of electric current. These questions came into your mind when your teacher told you about the heating effect. So, the Definition of the heating effect of electricity is “When a current passes through a conductor, the electrons in the conductor collide rapidly, and due to the collisions of these electrons, conductors produce heat energy. This effect is known as the heating effect of electric current.”

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We can define the heating effect of electricity as-

“When an electrical current is passed through a high resistance wire, like nichrome wire, the resistance wire becomes very hot and produces heat. This is called the heating effect of current.”

• Effects of heat: There are some effects of heat

• The temperature of the object rise

• On giving the heat the volume of the substance increases.

• On giving the heat to the solid substance or liquid substance, the state changes from solid to liquid and liquid to gas.

• A chemical reaction occurs on providing the heat.

• Physical properties of substances change on providing the heat.

• Electric room heater: Electric room heater or current heater is an electrical device. It is the best application of the heating effect of electric current. As we know, high resistance wire becomes hot and produces heat. So, a nichrome wire is used to make ‘heating elements' or ‘ heating coils’ which are used in the electric heater or current heater to produce heat. As electricity passes through it due to its high resistance it produces heat.

• The formula of heat in electricity: We will derive the formula of heat produced in electricity.

Derivation of heat effect of electric current.

Let an electric current I flowing through the conductor has resistance R. Due to electric current electric charge (q) flows against a potential difference V, to overcome this potential difference electric charge has to do some work. We will calculate the work done by the current I when it flows through a resistance R for time t. The amount of work done is given by:

W = q ✖ t …..(i)

By the definition of current, I = q/t

q = I.t …..(ii)

From ohm’s law, R = V/I

V = I.R ….(iii)

Now putting eqn (ii) and eqn (iii) in eqn (i), we get

W = I. t. I. R

W = I².R.t

All the electrical work done is converted into heat energy. So, work done is equal to the heat produced.

Heat produced, H = I².R.t joules.

This is the heat formula in electricity.

This formula of heat energy is also known as Joule’s Law of heating.

• Heating effect of electric current used in: Heating effect of electric current used in electric appliances such as electric iron, electric kettle, electric rod, room heater, oven, water heater (geyser), etc.

• On what principle electric bulb based: Electric bulb or current bulb is based on the principle of heating effect of electricity. When an electric current passes through a very thin, high resistance tungsten filament of an electric bulb, the filament becomes white-hot and emits light.

• Note- The same current flowing through the filament produces enormous heat but almost negligible heat is produced in the connecting wires of copper. This is because of the fact that the fine tungsten filament has very high resistance but the copper wire has very low resistance in comparison to tungsten. Image of electric bulb

Tungsten is utilized for making filaments of electric bulbs because it’s high melting point ( of 3380℃ ). Due to its high melting point, the tungsten filament will be kept white-hot without melting away. Tungsten filament has high flexibility and a low rate of evaporation at high temperature. If air is present in the electric bulb, then the extremely hot tungsten filament would burn up quickly in the oxygen of the air. So, the electric bulb is filled with a chemically unreactive gas like argon or nitrogen. These gases do not react with a hot tungsten filament and prolong the life of the filament of an electric bulb.

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• What is electric heating? It is a process of heating conductors when an electric current passes through them and conversion of electric energy into heating energy.

• Heating appliances: Electric heating appliances are electric iron, microwave, fuse, electric bulb, refrigerator, electric heater are some heating appliances.

• Thermal effect of electric current: As an electric current passes through the conductors, collisions between the electrons and atoms start in the conductor and due to collisions of electrons the temperature of the conductors rises and heat is produced.

• Heat current: Like electric current heat current is also the rate of flow of heat in the unit time.

• Methods of electric heating: The methods of electric heating are divided into two parts:

• Power frequency heating and high frequency heating.

• Power frequency is divided into three categories

• Direct resistance heating

• Indirect resistance heating

• Radiant heating heating

• High frequency heating is divided into two categories

• Direct induction heating

• Indirect induction heating.

• The wire used in the electric heater: The wire used in the electric wire is nichrome because it has high resistance.

• Magnetic effect of electric current: An electric current also produces a magnetic field. The ‘electromagnetic effect’ is known as the magnetic effect of electric current. The magnetic effect of electric current can be easily demonstrated by bringing a magnetic compass near a current-carrying wire. Place a magnetic compass on the wooden block, away from all magnetic substances. When a magnetic compass comes to rest, fix the wire over the compass, parallel to the needle. Connect the wire to a battery through a switch as shown in fig. Close the switch to pass a current through the wire. The compass needle gets deflected and comes to rest at right angles to its original position. If the direction of the current is from south to north, the north pole of the needle will come to rest pointing to rest.

Now hold the compass above the wire. The needle will get deflected in the opposite direction. The direction of deflection will also change if you reverse the direction of the current in the wire by interchanging the battery connection. If you switch off the current in the wire, the needle will go to its original position. This shows the magnetic effect of the current.

• Working of electric heater: The electric heater is based on high electrical resistance heating. This method of heating has 100% efficiency to convert the electrical energy into heat energy. When we pass the electric current through the electric heater then due to the high resistance heating element which is made up of nichrome the heating elements start to glow and produce heat.

• Equipment producing heat: In Electric equipment producing heat e.g., iron, toaster, electric heater, etc., an alloy such as nichrome is used because nichrome has higher resistivity than any other pure metals.

• Cause of heating effect: In an electric circuit, an electric current flows because of electric potential and electrons start flowing from the negative terminal to the positive terminal. To overcome this electric potential the electrons collide rapidly and produce heat. This is the cause of the heating effect.

• The special feature of electric wire: The electric wire must have high resistance and a high melting point.

• Use of heating effect of electric current: The heating effect of current is used in the working of electrical heating appliances such as iron, electric kettle, electric toaster, electric heaters, water heaters (geysers), etc.

• Working of iron: The electric iron is based on the heating effect of electricity. When we plug in, current starts to flow and the heating element gets heated and heat produces so iron becomes hot and we press it to the clothes to remove wrinkles. But due to continuous supply of current iron, heated up to danger level to prevent this ,iron has a thermostat. With the help of it, iron can regulate the temperature and prevent iron from being too hot to dangerous levels. The two

bimetallic strips made up of

Inase source science abc

two different metals have

different coefficients of

expansion and one of them has a low coefficient of expansion and the other has high. So when the temperature rises to its maximum value these strips bend upward and break the electric connection by opening the circuit. As temperature falls the strip comes to its initial state and current starts to flow by closing the circuit. This is also known as cut-off.

• The lighting effect of electric current: We read how the electric bulb works. When we switch on the electric bulb,the filament present in the electric bulb gets heated and starts to glow and lighting our house or street or any other place. The electric bulb which produces light is known as the lighting effect of electric current.

• Applications of heating effect of electric current: The important applications of the heating effect of electric current are given below:

• The heating effect of electric current is utilized in the working of electrical heating appliances such as electric iron, electric heater, electric toaster, electric oven, electric kettles, etc.

• The heating effect of electric current is utilized in the electric bulbs for producing light.

The heating effect of electric current is utilized in electric fuse for protecting household wiring and electrical appliances.

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