1e  qe =1.6021010-19 Coulomb mproton = 1836melectron mproton = 0.000 000 000 000 000 000 000 000 001 6748 kg melectron=0.000 000 000 000 000 000 000 000 000 0009 kg mproton = 1836melectron 1e  qe =1.6021010-19 Coulomb

How many electrons are there in 1 Coulomb of negative charge? How many protons are there in 1 Coulomb of positive charge?

Three pith balls are suspended from thin threads. Various objects are charged (rubbing glass against polyester, nylon against silk, rubber against fur, etc) and each pith ball is charged by touching them with one of these objects. It is found that pith balls A and B repel each other and that B and C repel each other. 1) A and C carry charge of opposite sign. 2) A and C carry charge of the same sign. 3) All three carry charge of the same sign. 4) Additional experiments are necessary to determine the sign of all charges.

Three pith balls are suspended from thin threads. Various objects are charged (rubbing glass against polyester, nylon against silk, rubber against fur, etc) and each pith ball is charged by touching them with one of these objects. It is found that pith balls A and B attract each other and that B and C repel each other. 1) A and C carry charge of opposite sign. 2) A and C carry charge of the same sign. 3) All three carry charge of the same sign. 4) Additional experiments are necessary to determine the sign of all charges.

1 2 3 4 Two uniformly charged spheres are firmly fastened by insulated stands to frictionless pucks which are set on an air table. The charge on sphere 2 is 3 the charge on sphere 1. Which force diagram correctly shows the magnitude and direction of the electrostatic forces? + + + + + + + + + + + + + + + + + + + + + + + + 1 2 + + + + + + + + + + + + + + + + + + + + + + + + 3 4

( 1 C )( 1 C ) (1 m2) = 8.9875109 N 0.2248 lb/N = 2,020,390,000 lbs What force exists between two concentrations of charge, each 1 coulomb separated center-to-center by 1 meter? ( 1 C )( 1 C ) (1 m2) = 8.9875109 N 0.2248 lb/N = 2,020,390,000 lbs = 1,010,195 tons

 = 15o 0.75 meters W  0.008 N 0.8 grams each assume 2 equally charged balloons (with uniformly distributed charge)  = 15o 0.75 meters 0.8 grams each W  0.008 N

 0.75 m x

 STRING’S TENSION ELECTROSTATIC REPULSION BALLOON’S WEIGHT

 F T T W F W

Felectric We can calculate the tan by W T/F T/W F/T F/W W/F W/T T 

 Felectric Felectric Felectric=(0.008 N)tan15o With tan15o= W W T

(8.9875109 Nm2/C2) q1q2 (0.388 m)2 0.002144 N = R = 0.388 meters W  0.008 N

A hydrogen atom is composed of a nucleus containing a single proton, about which a single electron orbits. The electrical force between the two particles is 2.31039 greater than the gravitational force! If we adjust the distance separating the two particles, can we find a separation at which the electrical and gravitational forces are equal? 1) Yes, by moving the particles farther apart. 2) Yes, by moving the particles closer together. 3) No, at any distance.