PHYS 272 Study Guide - Midterm Guide: Relative Permittivity, The Thirteen Chairs, Potential Energy

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17 Sep 2018
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Conductors in electrostatic equilibrium & electric potential energy 7. Charges and coulomb force: two types of electric charge: positive (+) and negative (-, opposite charges attract (+ to and to +) Like charges repel (+ from + and from ) All (cid:272)ha(cid:396)ges a(cid:272)t o(cid:374) ea(cid:272)h othe(cid:396) (cid:449)ith e(cid:395)ual a(cid:374)d opposite fo(cid:396)(cid:272)e (cid:894)ne(cid:449)to(cid:374)"s third law: units of charge. Smallest unit of charge is elementary charge (e) e =(cid:883). (cid:888)(cid:882)(cid:884) (cid:883)(cid:882) (cid:2869)9 c: building blocks of matter, matter is made up of protons, neutrons, and electrons. Protons and electrons have equal and opposite charges of e and e respectively: neutrons have no charge. See lecture notes for review of in class demo (charging glass rod w/fur, etc. ) Tells us the force with which two charges will attract or repel: coulo(cid:373)(cid:271)"s la(cid:449) Also written as (cid:1832)=(cid:1863)(cid:1869)(cid:2869)(cid:1869)(cid:2870)(cid:1870)(cid:2870) (cid:1832)= (cid:883)(cid:886)(cid:2024)(cid:2868)(cid:1869)(cid:2869)(cid:1869)(cid:2870)(cid:1870)(cid:2870) (cid:1863)= (cid:883)(cid:886)(cid:2024)(cid:2868)=(cid:890). (cid:891)(cid:890)(cid:889) (cid:883)(cid:882)9 nm(cid:2870)c(cid:2870) Two point charges +q and q are placed at r0 and +r0 on the x-axis.