Question

Give the four types of lamps working on the lighting effect of electricity.

Answer 1

Hint: The lamps which we use in our day-to-day life are all powered by the electric current. They consume electric energy to produce the light energy which helps us see around. The electric lamps can produce different colours according to its chemical structure.

Complete answer:
We use a wide variety of lamps in our daily life. Most of them use the electrical energy to be converted to the light energy. The four types of the lamps those use electricity to glow are:
1. The incandescent lamps: These are the normal electric bulbs with the tungsten filament in them. The tungsten metal becomes white-hot when enough potential is made available across its ends, thus producing light.
2. The Gas-discharge lamps: These consist of a pressure tube with cathode and anode terminal at each end. The electrons get ionised at cathode due to high potential difference and diffuse through the pressurised noble gas filled tube. The electrons collide with the gas particles which results in gaining of energy by the gas particles which are released as photons. These photons form the glow in the tube.
3. The Fluorescent lamps (CFLs): These lamps use the virtue of fluorescence of Phosphorus coated on a discharge tube with low pressure mercury vapour in it. When electric current passes through the mercury vapour, it excites the mercury atoms and triggers the release of ultraviolet rays which can help the Phosphor wall to glow.
4. The Light Emitting Diodes (LEDs): These are the most recent technology used in lighting using electricity. These lamps are p-n junction diodes which illuminate when the potential across the p-n junction is dropped by a forward bias such that the recombination of holes and electrons occur releasing photons of desired colour depending on the barrier energy gap.

Note:
The basic idea of formation of light energy is based on the molecular phenomena for all types of the lamps. The energy in any electric form is absorbed either to heat or excite the substance at molecular level. It is different from the light produced due to combustion.
Most of the electric lamps produce heat along with light.