108 lines
2.0 KiB
Plaintext
108 lines
2.0 KiB
Plaintext
Electric Charges and Fields Part -1
|
||
Electric Field
|
||
Charges are additive in nature.
|
||
q1
|
||
q2 q3
|
||
q1 q2 q3
|
||
Q=
|
||
Q
|
||
++
|
||
Like charges repel;Unlike charges attract
|
||
+
|
||
|
||
|
||
|
||
+
|
||
+
|
||
} Repel
|
||
Attract
|
||
+ve
|
||
-ve
|
||
Charges
|
||
COULOMB’S LAW
|
||
r
|
||
Fe = kq1q2
|
||
r2
|
||
F21= q1 q2
|
||
r2
|
||
21
|
||
1 4 Ꮛ0
|
||
q1 q2
|
||
k= 1
|
||
4 Ꮛ0
|
||
Ꮛ0 = permittivity of vaccum
|
||
=8.854 x 10-12C 2N-1m2
|
||
Vector form of Coulomb’s Law
|
||
r21 r21= r2-r1
|
||
F21= -F21
|
||
A region around a charged particle or object within which a force would be exerted on other charged particles or objects.
|
||
E=E 1 + E 2 +......+ E n
|
||
= kq 1 /r 1
|
||
2 + kq2 /r 2
|
||
2 +..... + kq n /rn
|
||
2
|
||
It is equal to the electric force per unit experienced by a test charge whi
|
||
The electric field intensity is the measure
|
||
strength of an electric field at any E= =
|
||
F q
|
||
E= k.Q
|
||
d2
|
||
= k.Q
|
||
d2
|
||
k . q. Q/d 2 q/
|
||
/
|
||
Newton / Coulomb
|
||
Electric Field Lines: Properties
|
||
Electric field lines start from a positive charge and end at a negative charge.
|
||
In case of a single charge, electric field lines end at infinity.
|
||
In a charge-free region, electric field lines are continuous and smooth.
|
||
Two electric field lines never intersect or cross each other.
|
||
Electric field lines never form a closed loop because electric field is conservative in nature.
|
||
+_
|
||
+_
|
||
Field lines
|
||
The electric field from an isolated positive charge
|
||
The electric field from an isolated negative charge
|
||
+
|
||
+
|
||
Cable jacket A leg insulator B leg insulator Conductors
|
||
Electrical Conductors Electrical Insulator
|
||
Conductors have free electrons on the surface which allows current to pass through. Insulators don’t.
|
||
Electric charge is quantized.
|
||
Q=n e
|
||
x
|
||
( NC-1)
|
||
The electric field intensity between two points is the vector sum of all the electric fields acting at that point.
|
||
Charge is a conserved quantity.
|
||
Net Charge q=0 (neutral)
|
||
gains 2 electrons loses 2 electrons
|
||
Steel Wood
|
||
Glass Rubber
|
||
Plastic Oil
|
||
Silver Gold
|
||
Sea
|
||
Water
|
||
Copper
|
||
CONDUCTOR
|
||
a
|
||
llows
|
||
the
|
||
energy
|
||
to
|
||
pass
|
||
through
|
||
it
|
||
INSULATOR
|
||
does
|
||
not
|
||
a
|
||
llows
|
||
the
|
||
energy
|
||
to
|
||
pass
|
||
through
|
||
it
|
||
of the point.
|
||
charge
|
||
ch is placed at that point |