Introduction Flashcards
What are static charges ?
The charges which are at rest or do not move or change with time are called as static charges.
What is electrostatics ?
It is a branch of physics which deals with the study of the charges which are at rest , I.e static charges , the forces between the static charges , their fields and their potentials is called as e.s , static electricity or frictional electricity.
Electric charge phenomenon discovered by
Thales of Miletus in 600 BC in amber
Amber rubbed with wool or silk cloth attracts light objects.
What is electric charge acc to Sir William Gilbert?
Electric charge is something possessed by all material objects which enables them to exert an electric force and also respond to an external electric force.
How did they come to the conclusion that proton and electron carry the same charge?
Two electrons or protons kept at a distance of 1 cm away from each other repel each other with the same force. I.e 2.3 x 10 - 24 .
How did they find out that neutrons had no charge ?
Neutrons only exhibited attractive or gravitational force due to their mass , but never an additional electric or large magnitude force.
The property which differentiates the two kinds of charges is
The polarity of the two charges.
Like charges repel.
Unlike charges attract.
Why are two charges called positive and negative
?
The charges acquired by the object on rubbing against each other must be equal and opposite. Because one loses and the other gains.
The opposite charges nullify each other’s effect.
Like positive and negative numbers become zero
So Benjamin Franklin called them positive and negative.
What is a Gold Leaf Electroscope ?
It is an instrument used to detect the presence of electric charge and also its polarity.
By measuring the divergence of leaves the amount of charge can be estimated.
To identify the polarity a gold leaf electroscope which is already charged is used.
What are conductors ?
The materials which can be used to conduct electricity from one end to the other or the materials which allow the movement of charges through them are called as conductors.
Insulators
The materials which do not allow the movement of charges through them or are the poor conductors of electricity.
Semiconductors
The materials whose resistance to the flow of charges is between that of the conductors and insulators are called semi conductors.
Electrification
The process of creating a surplus or deficit of electrons in an object.
What is meant by charging by friction ?
When two bodies are rubbed against each other , electrons are transferred from one body to the other.
The body which loses electrons gets positively charged and the body which gains electrons gets negatively charged.
What is meant by charging by conduction ?
When a charged body is bought in contact with an uncharged conductor , the charges flow from the charged body to the uncharged body.
The charge acquired by the conductor is same as the charge of the charging body.
