Laws describing behaviour between charged and uncharged objects 1. Unlike charges attract 2. Like charges repel 3. Charged objects attract uncharged (neutral) objects

Unit 4 - Topic 1 Flashcards by Wani Ader

Static electricity

A charge produced by rubbing or touching objects together

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Unbalanced charges

A more correct term for static electricity cuz charges are non stationary; rather they move

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Laws of Charges

Laws describing behaviour between charged and uncharged objects

Unlike charges attract
Like charges repel
Charged objects attract uncharged (neutral) objects

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Insulators

Any material in which charge stays on spot where object is rubbed

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Conductors

Materials that allow charges to move freely

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Superconductors

Materials that offer little or no resistance to the flow of charges

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Electric discharges

Small sparks 
Serious safety hazards 
Can:
Shock ppl
Damage electronic equipment 
Cause fires and explosions

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Neutralized

Became balanced

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Grounding

Connecting an object to Earth with conduction wire to safely rebalance a charge

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Most non-metals are …

Insulators

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Most metals are …

Conductors

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Electric charges produced

Materials rubbed, touched, moved closer together then separated

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Electroscope

Instrument detecting electric charge

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Dosimeters

Pocket-sized electroscopes
Used to measure exposure to atomic radiation
Charged particles produced by radiation detected by it
Strict limits to radiation exposure

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Difficult to … electric charge …

Measure

Directly

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Quantity of electric charge expressed in

Coulombs (C)

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Van de Graaff generator

Produces large electric charges on metal sphere

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Neutral (“uncharged”)

Equal + and - charge

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+ vs. - charge

Excess + charge vs. -

Benjamin Franklin

1706-1790

1st using terms + and - to describe charges

Charge left on amber jabbed w/ fur/Franklin

Negative

Charge left on fur/Franklin

Positive

2 dif. charges, 1 + and -

Unlike charges

2 same charges (both + or -)

Like charges

Franklin understood

All matter consists of atoms Which contain protons and electrons Helped establish Laws of Charges

Hold electrons loosely

Conductors

Hold electrons tightly

Insulators

Allow electrons to move but not at all freely

Fair conductors

Semiconductors conductivity increased

By implanting foreign atoms into otherwise pure material

Silicon w/ gallium added | Germanium w/ phosphorus added

Commonly used superconductors

-137.15 C to -273.15 C

Temps certain materials become superconductors at

Superconductors con

Need low temps

Superconductors used for

Electrical generators High-voltage power lines Supercomputers

Superconductors pros

Take up less space Can carry higher charges than ordinary ones 7000% space efficient

Fair conductors

Allow electrons to move, but not at all freely

Modern theory

Unbalanced charges on solid materials dure to movement of electrons form one object to another

Why unbalanced better than static

Instances when charges move so static kinda of inaccurate

Metal alloys and ceramics

Superconductors

Increased by adding foreign atoms into otherwise our material

Conductivity

Gasoline trucks/highway

Blowing wind/dust over bumpy roads | Becomes charged

Trucks always … before delivering gasoline

Grounded

Grounding of trucks prevents

Sparking | Could cause fumes to explode

Movement of gasoline through hose produces

Charges

Grounding cable remains attached when

Before and during delivery

Hand-held ionizers

Neutralize electrostatic charges on non-conductors