Special resistor materials: carbon, Physics

Carbon:

Atomic number

6

Symbol

C

Atomic weight

12.011

Discovery

Carbon exists free in nature and has been known since prehistoric time.

Electronic configuration

[He] 2S2 2p2

Word origin

Latin name carbo, French name carbon, coal or charcoal.

me n contact Melting point

34500C

Electrical resistivity

400-1200*10-8 ohm-m.

Properties:

1.      Carbon is found free in three forms: Amorphous, Graphite and Diamond.

2.      It has negative temperature coefficient of resistance.

3.      Its resistance is pressure sensitive. As pressure increases electrical resistance of the carbon emcontact decreases.

4.      It can withstand arcing.

5.      It has not a very good abrasive resistance.

6.      Diamond is one of the hardest substances with a high melting point and index of refraction.

Uses:

1. Carbon is used in applications like brushes for electrical machines electrodes for electric arc furnaces non wire resistors battery cell element are lamps are welding etc.

2. Carbon is also used in some telecommunication equipments like potentiometers microphones etc.

3. Diamond is prized as a gemstone and is used for cutting, drilling and as bearing.

4. Graphite is used as crucible for melting metal, in pencils, for rust protection, for lubrication, an as a moderator for showing down neutrons for atomic fission.

5. Amorphous carbon is used for removing tastes and odours.

Posted Date: 7/21/2012 7:50:24 AM | Location : United States







Related Discussions:- Special resistor materials: carbon, Assignment Help, Ask Question on Special resistor materials: carbon, Get Answer, Expert's Help, Special resistor materials: carbon Discussions

Write discussion on Special resistor materials: carbon
Your posts are moderated
Related Questions
Get an expression for work done during reversible isothermal expansion. Get the terms open, isolated and closed system. Give examples.

Why nuclear fission preceeds nuclear fusion?

Define about the Graphite Structure   Graphite is the allotropic form of carbon. In case of graphite the carbon atoms are arranged in regular hexagons in flat parallel layers a

assignment for types of diodes ?

Describe NOR and NAND gates. Provide their truth tables. Discuss the nature of a p-n junction. How does a potential barrier develop at the junction.

What is the resistance of a coil of aluminium wire The resistance of a coil of aluminium wire at 18 ? C is 200?. The temperature of the wire is increased and the resistance

Aluminium   Atomic number 13 Symbol Al Atomic weight 26.98154 Discovery W


A small air bubble is placed 0.04 m inside a glass sphere of refractive index 1.5. When viewed normally from outside it is seen at a depth of 0.03 m. Determine the radius of curvat

What is the Directionality of LASER? Directionality: Laser emits light which is highly directional. Laser light is emitted like a relatively narrow beam in an exact direction.