static electricity

All matter consists of what three charges?

Protons, electrons and neutrons

In metals are electrons fixed or mobile?

Mobile

In metals are protons fixed or mobile?

Fixed

When is an object considered one with a neutral charge?

When they have an equal number of positive and negative charges.

Like charges…

Repel

Unlike charges…

Attract

Coulomb's Law

The force of attraction or repulsion is inversely proportional to the square of the separation between 2 charges.

How can static charge be acquired?

By rubbing a hard insulator with a soft insulator.

What charge does a polythene rod have when rubbed with cloth?

Negative

Acetate rod when rubbed with cloth?

Positive

Perspex when rubbed with cloth

Positive.

Charging by contact

An uncharged conductor can be charged using a charged conductor.

Charging by induction

the rearrangement of electrons on a neutral object caused by a nearby charged object

Give an example et changing by conduction.

At the beginning, the neutral sphere has no charge.there is repulsion between the negative charge on the rod and the similar charges on the sphere causing them to flow away from the rod. The deficiency of electrons produces a positive charge on the far side and the excess electrons produce an equal negative charge on the other side. Touching the sphere with a finger allows elections to flow further away to earth. Remove the finger so that escaped electrons can't return leaving the sphere with a permanent deficiency of electrons hence a positive charge- remove the charging rod to let the positive charge spread.

What is static electricity?

When electrons from one object get transferred to the surface of another object.

Friction produces…

Charge

Note

Only repulsion confirms that an object is charged.

Why can a charged object attract an uncharged one?

When the object's surface has no charge the side facing the charged strip will be depleted of electrons and have an induced positive charge o then the negatively charged strip attracts the object because it sees the opposite positive charge on the near side.

The action of points

Electric charge concentrates at points. The more pointed something is the higher the concentration of charge.

Example of the action of points.

A negatively charged thunder load induces a positive charge on buildings and the ground below. The positive charge is concentrated at the tip of the lightning conductor- this attracts electrons from the load and repels positive ions into the air. This causes a steady flow of negative charge away from the cloud discharging it.in the event that lightning does strike it would discharge down the lightning conductor