Electromagnetism revision
Electromagnetism revision
Electric fields Chapter 16
Chapter 16 Electric fields
Charge is quantized(量子化). Everything is charged in multiples of e the elementary charge(except quarks
Charge is quantized (量子化). Everything is charged in multiples of e, the elementary charge (except quarks!)
Charge is conserved(守恒的) The total charge of the universe never changes
Charge is conserved (守恒的). The total charge of the universe never changes
Electric field of one point charge E Observation location Source charge 二 丌C 0 Coulombs Law
Electric field of one point charge r r q E ˆ 4 1 2 0 = q Coulomb’s Law
E= q 4 2 g is positive the direction of the field is away from the charge
+ r r q E ˆ 4 1 2 0 = q is positive: the direction of the field is away from the charge
E= q 4 2 g is negative the direction of the field is towards the charge
- r r q E ˆ 4 1 2 0 = q is negative: the direction of the field is towards the charge
Superposition Principle 电场强度叠加原理 F4=geNet t 92V 4(+E2+E 3 1 Location of ge 4 E E ne
Superposition Principle 电场强度叠加原理 - + q1 q2 ( ) 4 1 2 3 4 4 net q E E E F q E = + + = q + 3 Location of q4 E1 E2 Enet E3
Superposition Principle 电场强度叠加原理 In general: net s e +2+b2+ or het s The net field at a location in space is the vector sum of the fields contributed by all charged particles at other locations
Superposition Principle 电场强度叠加原理 Enet = E1 + E2 + E3 + In general: = i E Ei net or: The net field at a location in space is the vector sum of the fields contributed by all charged particles at other locations
Dipole 电偶极子 H C Hydrogen chloride Water
-q +q Dipole 电偶极子 d + - Hydrogen chloride + - Water O H H
