project = use of heating effect of electric current in daily life applications, what is its need and important?
Answers
Answer:
When an electric current is passed through a conductor, it generates heat due to the hindrance caused by the conductor to the flowing current. The work done in overcoming the hindrance to the current generates heat in that conductor. As a result, the resistance wire (mainly, high resistance wires, like nichrome wire) becomes very hot and produces heat.
This is called the heating effect of current.
According to the law of conservation of energy, the total energy in a system is always constant. Thus, when we convert electricity to other forms of energy, some energy is converted to useful work, but a certain amount is converted to heat energy.
The heating effect of electric current is widely used in our day-to-day life. The electric iron, kettle, toaster, heater, etc. are used as alternatives to the conventional methods of cooking and laundry. The same is used in electric bulbs which is the alternative of conventional lamps. These devices have revolutionized the world over the years.
Following are the devices in which heating effect of current is harnessed for other purposes:
-Electric Iron: Mica is an insulator that is placed between the metal part and the coil in an iron. The coil becomes heated with the passage of current which is then transferred to the metallic part through mica. Finally, the metal part becomes heated which is then used for ironing clothes
-Electric Bulb: Electric bulb contains a thick metallic wire made up of tungsten metal. The metal is kept in an inert environment with a neutral gas or vacuum. When current flows through the tungsten wire, it becomes heated and emits light. Most of the electric power drawn in the circuit from the electrical source is dissipated in the form of heat and the rest is emitted in the form of light energy.
-Electric Heater: In an electric heater, high resistance nichrome wire is used as a coil. The coil is wound on grooves made up in ceramic material or china clay. When the current flows in the coil, it becomes heated, which is then used to heat cooking vessels.
-Electric Fuse: In any electrical instrument, due to sudden rise of current, the instrument gets burnt down which sometimes results in fire. A conducting wire with low melting point is connected in series with the circuit to avoid this type of accident. When the current rises, the wire melts due to excessive heating, thus breaking the electrical circuit.
Note
This phenomenon was observed by James Prescott Joule in the 19th century. He passed a current-carrying wire through water and noted the rise of the water’s temperature for a span of 30 minutes. He tried different combinations of wire lengths and the amount of current flowing through them. He finally deduced that the heating effect of current is proportional to the current flowing through the wire and the resistance value of the material. This kind of heating does not depend on the direction of the current flow.