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