Why is the charge on a glass rod rubbed with silk positive and not negative?

Asked by megha17 | 16th Mar, 2009, 10:41: PM

Expert Answer:

The transfer of charge depends on the two materials. Materials can be ranked according to their tendency to gain or loose electrons in a triboelectric series. So you can see that glass would tend to acquire a more positive charge than silk, which means that electrons would go from glass to silk.

The following table has been picked from

http://www.siliconfareast.com/tribo_series.htm

Table 1.  The Triboelectric Series

Most Positive (+)

Air

+++

 

 

 

 

 

 

+

Human Hands, Skin

Asbestos

Rabbit Fur

Glass

Human Hair

Mica

Nylon

Wool

Lead

Cat Fur

Silk

Aluminum

Paper

Cotton

 

Steel

-

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

- - -

Wood

Lucite

Sealing Wax

Amber

Rubber Balloon

Hard Rubber

Mylar

Nickel

Copper

Silver

uv Resist

Brass

Synthetic Rubber

Gold, Platinum

Sulfur

Acetate, Rayon

Polyester

Celluloid

Polystyrene

Orlon, Acrylic

Cellophane Tape

Polyvinylidene chloride (Saran)

Polyurethane

Polyethylene

Polypropylene

Polyvinylchloride (Vinyl)

Kel-F (PCTFE)

Silicon

Teflon

Silicone Rubber

Most Negative (-)

 

Answered by  | 19th Mar, 2009, 05:07: PM

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