Electrostatic : Electrostatic 1.Electric charge
2.Two kinds of charges
3.Properties of charges
4.Coulomb’s law
Electric Charge : Electric Charge The branch of Physics, which deals with the study of charges at rest, the forces between the static charges, fields and potentials due to these charges is called Electrostatics or Static Electricity or even Frictional Electricity.
Charge is something possessed by material objects that makes it possible for them to exert electrical force and to respond to electrical force.
Kinds of Charges : Kinds of Charges 1.Positive charge-Glass rod, fur etc.
2.Negative charge-silk, ebonite rod etc.
Properties of charges : Properties of charges The following are a few important properties of electric charge:
1.Like charges repel each other and unlike charges attract each other.
2.The magnitude of elementary negative or positive charge is same and is equal to 1.6×10⁻¹⁹ C.
3.The electric charge is additive in nature. It implies that total charge on an object is algebraic sum of the charges located at different points in the object.
4.The charge is quantized i.e. charge carried by a charged object is equal to ±ne,where n is an integer.
5.The electric charge of a system is always conserved.
6.Unlike mass, the electric charge on an object is not affected by the motion of the object.
Additive nature of charge : Additive nature of charge The total electric charge on an object is equal to the algebraic sum of all the electric charges distributed on the different parts of the object.
q=q₁+q₂+q₃+q₄+….
It may be pointed out that while taking the algebraic sum, the sign of the electric charges must be taken into account.
Quantization of charge : Quantization of charge The fact that all observable charges are always some integral multiple of elementary charge ‘e’ is known as quantization of charge or discrete nature of charge.
q=±ne
where q-charge
n-integer
e-charge of electron.
Conservation of charge : Conservation of charge It states that for an isolated system, the net charge always remains constant. In other words, charge can neither be created nor destroyed.
For example ₀n¹+₉₂U²³⁵→₅₆Ba¹⁴¹+₃₆Kr⁹²+3₀n¹+energy
Coulomb’s Law : Coulomb’s Law It states that two point charges attract or repel each other with a force which is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance between them.
F ∞ q₁q₂/ r²
F=1/4∏ε₀ q₁q₂/r²
ε₀-8.854x10¯¹²C²N¯¹m¯²
Cont… : Cont… ε₀-absolute permittivity of free space
F=9x10⁹ q₁q₂/ r²