Electric Fields and Charge Distributions: Homework and Announcements
This announcement provides important information about homework assignments related to Chapter 26 on electric fields. Students are tasked with completing conceptual questions (CQs) and problems (Probs) pertaining to electric fields of rings, disks, and planes, among other topics. Additionally, office hours for assistance and availability of the Tutorial Learning Center (TLC) are included. Make sure to understand linear and surface charge densities and their effects on electric fields. Attend office hours for clarification on challenging concepts.
Electric Fields and Charge Distributions: Homework and Announcements
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Presentation Transcript
Announcements • Homework for tomorrow… (Ch. 26 CQs 8, Probs. 13 & 15) 25.62: E1 = (4.0 x 104 N/C) ihat + (8.0 x 104 N/C) jhat, E2= (4.5 x 105 N/C) ihat, E3 = (4.0 x 104 N/C) ihat- (8.0 x 104 N/C) jhat 26.3: E = 1.1 x 104 N/C, 10° below x-axis 26.5: E = (36 N/C) ihat at (0.10 , 0) m, E = -(18 N/C) ihat at (0 , 0.10) m • Office hours… MW 12:30-1:30 pm TR 9-10 am F 10-11 am • Tutorial Learning Center (TLC) hours: M 8-1 pm, 3-6 pm, W 8-1 pm, 2-6 pm TR 8-6 pm, F 8-2 pm
Chapter 26 The Electric Field (The E-Fields of Rings, Disks, & Planes)
Last time… • Linear & surface charge densities • E-field of a rod of length L & charge Q in the bisecting plane.. • E-field of an infinite line charge.. + + + + + + + + + + + + + + + + + + + r L P
Quiz Question 1 Two protons, A and B, are in an E-field. Which proton has the larger acceleration? • Proton A • Proton B • Both protons have the same acceleration
i.e. 26.4E-field of a ring of charge.. A thin ring of radius R is uniformly charged with total charge Q. Find the E-field at a point on the axis of the ring (perpendicular to the ring).
i.e. 26.4E-field of a ring of charge.. A thin ring of radius R is uniformly charged with total charge Q. Find the E-field at a point on the axis of the ring (perpendicular to the ring). • Q: What about for –z? • Q: What about for –Q?
Quiz Question 2 Positive charge +Q is uniformly distributed on the upper half of a semicircular rod and negative charge –Q is uniformly distributed on the lower half. What is the direction of the electric field at point P, the center of the semicircle? • Up. • Down. • Left. • Right. • Up and to the left. +Q P -Q
E-field of a disk of charge.. A disk of radius R is uniformly charged with total charge Q. Find the electric field at a point on the axis of the disk (perpendicular to the disk).
E-field of a disk of charge.. A disk of radius R is uniformly charged with total charge Q. Find the electric field at a point on the axis of the disk (perpendicular to the disk). Notice: • For z<0, same magnitude but opposite direction
E-field of a plane of charge.. A planeis uniformly charged with uniform surface charge density η. Find the E-field… + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + ∞ ∞
E-field of a plane of charge.. A planeis uniformly charged with uniform surface charge density η. Find the E-field… + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + ∞ ∞ Notice: • A constant! • Zero height dependence?
Quiz Question 3 Two protons, A and B, are next to an infinite plane of positive charge. Proton B is twice as far from the plane as proton A. Which proton has the larger acceleration? • Proton A. • Proton B. • Both protons have the same acceleration.
E-field of a sphere.. A sphere of charge Q and radius R (uniformly charged or a spherical shell) has an E-fieldof the form… • Exactly the same as that of a point charge!
