Electric Current (Physics) Part-I

Fuse is a piece of wire with high resistance and very low melting point. When a high current flows through the circuit, it gets heated and melts.

Fuse is a piece of wire with high resistance and very low melting point. When a high current flows through the circuit, it gets heated and melts.

The filament of a halogen lamp is an alloy of tungsten and sodium. Due to the presence of sodium in filament, it produces yellow light.

When electric current passes through the conducting wire, moving electrons continuously collide with the atoms of the conductor.

In this process, they transfer their energy to the atoms of the conductor and therefore, temperature of the conductor increases. Thus, assertion (A) is correct but reason (R) is false.

Domestic electrical wiring is basically a parallel connection. In parallel circuit, each branch receives equal current. In a parallel connection if one of the bulbs is removed from the circuit i.e. if one of the branches in the circuit is broken, electric current will still flow in other branches and other bulbs will continue to glow.

The electric power line reaches our house through three wires namely a live wire, neutral wire, and earth wire. To avoid confusion we follow a colour code for insulating these wires.

The red wire is a live wire, and the black wire is neutral. The earth wire is given green plastic insulation.

The order of magnitude of electric resistance of the human body (dry) is generally in the range of 10⁴ (10000) ohms and it may be as high as 10⁵ (100000) ohms or more. Wet or broken skin may drop the body's resistance to 1000 ohms or less.

C.F.L. is short form of Compact Fluorescent Lamp. CFL uses significantly less energy than traditional light bulbs (about 75% less).

Light Emitting Diode (LED) work on the Principle of Electroluminescence. Electroluminescence (EL) is an optical and electrical phenomenon in which a material emits light in response to the passage of an electric current or to a strong electric field.

It is the result of radiative recombination of electrons and holes in a material, usually a semiconductor. The excited electrons release their energy as photons-light.

A light-emitting diode (LED) is a semiconductor light source that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons.

In Light Emitting Diode (LED) Lamps, gallium arsenide is used as main light emission component which converts electric energy into light. Its life span is greater than that of CFL because LED lamps consumes less energy-than CFL.