C & S Chapter 8 Homework Answers

hwk 8-1. Given the capacitor as described, the electric field is constant everywhere inside the plates and directed left to right. It's value is E = Q/(ıR2 e0) .

Since DV= -E. DL = - E DL cos u, where u is the angle between E and DL DVDC = DVAD = 0, (cuz u = 90°), anD
a-1) DVABC = DVAB + DVBC = - E s1 cos(180°) + 0 = E s1.

a-2) DVAC = -E DL cos u = -E (-s1) = E s1 (see figure at right )

a-3) DVADBC = DVAD + DVDB + DVBC
= 0 + (-E)(-s1) + 0 = E s1

b) DVAC =

 

Hwk8-2: Have DVAB = 1.5 V

Which end has higher potential? B
Magnitude and direction of E inside the resistor? E = 1.5V / 10-2 m = 1500 V/m toward A.