Chapter 1 Electric Charges And Fields Flashcards
What is an example of electric discharge?
Lightning during a thunderstorm
Why do we experience an electric shock?
These experiences are due to discharge of electric charges caused due to their accumulation by rubbing of insulating surface.
What do you mean by Statics?
Anything that does not move or change with time
What does Electrostatics deal with?
It deals with forces, fields and potentials.
Who discovered that amber rubbed with wool or silk attract light objects?
Thales of Miletus,Greece
Electricity is coined from the word….
Elektron in Greek meaning amber
After years of careful study, scientists found…
There are two types of entities called electric charge
How can electrification occur?
On rubbing
The pith ball experiment suggests two types of electrification, what are the conclusions?
Like charges repel
Unlike charges attract
What is the property that differentiates two types of charges?
Polarity
When two oppositely charged bodies are brought in contact, what happens.
The charges neutralize or nullify each other’s effect
Benjamin Franklin named the charges as
Positive and Negative
Glass rod and cat’s fur are
Positive
Plastic rod and silk are
Negative
When an object possess charge it is
Electrified
When an object has no charge it is
Electrically neutral
An apparatus used to detect the charge on the body
The gold leaf electroscope
The amount of charge is indicated by
Degree of divergence
All objects are electrically neutral, why?
They possess charges but they are equally balanced
Forces holding molecules together, forces that hold atoms together in a solid, the adhesive force of glue, force associated with surface tension are
All electrical in nature, arising from the force between two charged particles.
During rubbing….
No new charges are created
The electrons transferred during rubbing are just a
Small fraction of the total number
Substance which allow electricity to easily pass through it is
Conductor. The electric charges are free to move around
Substances that offer higher resistance
Insulator
A substance in between conductors and insulators
Semiconductors
In conductors:
Charge is easily distributed
In insulators:
Charges remain in the same place
Charging can be done by….
Contact
Charging by induction occurs……
Instantly
There is no loss of charges during the process of …..
Charge by induction
How are light objects attracted?
By the process of of charge by induction
The centres of the opposite charges are found to be separated, but due to induction…..
The force of attraction overcomes the force of repulsion
How do we consider the charges?
As point charges which are concentrated
Additivity of a charge
The charge is:
-Scalar(magnitude, can be added)
- it can be positive or negative
Charge is conserved
-in an isolated system net charge can neither be created nor destroyed
- in the process the charge carrying particles can be destroyed
- redistribution happens to maintain the charge
Quantization of charge is
q=ne
What is the unit of charge ?
Coulomb(C)
e=
1.6×10^-19C
For 1 C=
6.25×10^18 electrons
At the the macroscopic level
Quantization of charge is observed as a stream
