{Again recall that: k = } the charge on the sphere is (–) the -field is radially inward toward the center of the sphere i.e., in the direction. Writing the -field in vector notation: Answer: Note that [III b] says that the -field outside a charged spherical conductor is the same as if all the charge were concentrated at the center of the sphere, i.e., as if it were a point charge at the center of the sphere. Note also that [II b] says the same for a non-conducting sphere since in the answer to [II b] if we let Q represent the total charge distributed in the sphere then since then where the direction of the -field is determined by whether Q is (+) or (–). As further practice in using Gauss’ Law work problems 7 through 12 at the back of this unit. End Unit II – – In-Text Fill-in Answers Page Fill-in # Fill-in Answer II-4 1 for a straight wire. R is proportional to 1/E. If E is decreased by a factor of 1/5 (i.e., from 10 N/C to 2 N/C) then R increases by a factor of 5. Hence, when E = 2 N/C the point is 5R from the wire. 2 a) The -field is in the direction of the force on a (+) charge. Since the wire is charged (+), the electric field is directed radially outward from the wire. = 1.8 N/C, radially outward from the wire b) = 0.9 (–outward) = 0.9 inward toward the wire 3 If the point charge is to remain at rest then
{Again recall that: k = } the charge on the sphere is (–) the -field is radially inward toward the center of the sphere i.e., in the direction. Writing the -field in vector notation: Answer: Note that [III b] says that the -field outside a charged spherical conductor is the same as if all the charge were concentrated at the center of the sphere, i.e., as if it were a point charge at the center of the sphere. Note also that [II b] says the same for a non-conducting sphere since in the answer to [II b] if we let Q represent the total charge distributed in the sphere then since then where the direction of the -field is determined by whether Q is (+) or (–). As further practice in using Gauss’ Law work problems 7 through 12 at the back of this unit. – End Unit II – In-Text Fill-in Answers Page Fill-in # Fill-in Answer II-4 1 for a straight wire. R is proportional to 1/E. If E is decreased by a factor of 1/5 (i.e., from 10 N/C to 2 N/C) then R increases by a factor of 5. Hence, when E = 2 N/C the point is 5R from the wire. 2 a) The -field is in the direction of the force on a (+) charge. Since the wire is charged (+), the electric field is directed radially outward from the wire. = 1.8 N/C, radially outward from the wire b) = 0.9 (–outward) = 0.9 inward toward the wire 3 If the point charge is to remain at rest then