In this chapter, we will study two natural phenomena
- Lightning
- Earthquake
To learn about Lightning, we should first know what an electric charge is
What is Charge
It is the amount of electricity contained in an object
There are 2 types of charges
- Positive Charge
- Negative Charge
How is charge obtained?
It is obtained by friction caused by rubbing of 2 objects.
What are Different Rules of Charge?
There are two rules of charges
- Like Charges Repel Each other
- Unlike Charges Attract Each other
Like Charges Repel Each other
It means that if we bring 2 objects which have the same charge (both positive or both negative) together, they repel each other.
Example
Suppose we rub 2 balloon against wall, they become negatively charged.
If we bring both of them together, they repel each other
Similarly, if we bring 2 objects which are positively charged together
they repel each other
Unlike Charges Attract each other.
It means that if we bring 2 objects, one Positively Charged and one Negatively Charged together,
they attract each other
Example
Suppose we rub a glass rod with silk, it becomes positively charged.
Similarly, if we rub a balloon against the wall ,it becomes negatively charged
Now, if we bring this charged glass rod with charged plastic straw, both attract as one is positively charged and other negatively charged
Movement of Electric Charges
Static Charge
Charge which does not move by themselves is called static charge
Charge which is generated by rubbing is static charge
Electric Current
When charge moves, it constitutes Electric Current
Example
Current which make bulb glow.
Current which make wire heat
Questions
NCERT Question 8 - Explain why a charged balloon is repelled by another charged balloon whereas an uncharged balloon is attracted by another charged balloon?
NCERT Question 2 - When a glass rod is rubbed with a piece of silk cloth the rod
(a) and the cloth both acquire positive charge.
(b) becomes positively charged while the cloth has a negative charge.
(c) and the cloth both acquire negative charge.
(d) becomes negatively charged while the cloth has a positive charge
NCERT Question 3 (b) - Write T against true and F against false in the following statements:
A charged glass rod attract a charged plastic straw (T/F)
