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PHYS 2326 Electromagnetism and Waves Dr. Phillip C. Anderson. We will be studying the laws of electromagnetism from a very “advantageous” position as an already existing great and consistent picture – we won’t be deducing these laws but rather applying them in simple situations.
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PHYS 2326 Electromagnetism and Waves Dr. Phillip C. Anderson
We will be studying the laws of electromagnetism from a very “advantageous” position as an already existing great and consistent picture – we won’t be deducing these laws but rather applying them in simple situations. Remember however that it is a great body of experimental evidence on the basis of which and to rationalize which this picture was developed!
Electric charges (not quite like mass): • Of two kinds: positive (like protons) and negative (like electrons). Like charges repel each other; unlike charges attract • (Total) charge is conserved (even when particles are created or annihilate) • Charge is quantized – exists only in integral multiples of the fundamental charge Electric and magnetic forces (just as gravity) are fundamental forces of nature Electric charge (just as mass) is a fundamental characteristic of particles
Conductors are materials in which charges can move freely – will always move while E is present In insulators charges cannot move freely (but can be displaced with respect to each other) Charging by induction Grounding – charges can flow to the Earth
unit vector Coulomb’s Law Force produced by “point” charge 1 on “point” charge 2: