Announcements
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Announcements Homework for tomorrow… Ch. 25, Prob. 65 & Ch. 26, CQ 2, Probs. 4 & 6 CQ12: 3 rd line to the right of -q 25.18: F A =(7.2 x 10 -4 N) jhat, F B =-(7.2 x 10 -4 N) jhat 25.40: F=(1.2 x 10 -5 N) jhat Office hours… MW 12:30-1:30 pm TR 9-10 am F 1-2 pm Tutorial Learning Center (TLC) hours: ??
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Announcements. Homework for tomorrow… (Ch. 25 Prob. 62, Ch . 26 Probs. 3 & 5 ) CQ13: a) 4 F b) 4 F 25.12: a) 0.90 N b) 0.90 m/s 2 25.35 : 4.3 x 10 -3 N, 252° CCW Office hours… MW 12:30-1:30 pm TR 9-10 am F 10-11 am Tutorial Learning Center (TLC) hours: - PowerPoint PPT Presentation
Transcript of Announcements
Announcements Homework for tomorrow…
Ch. 25, Prob. 65 & Ch. 26, CQ 2, Probs. 4 & 6
CQ12: 3rd line to the right of -q25.18: FA=(7.2 x 10-4 N) jhat, FB=-(7.2 x 10-4 N) jhat25.40: F=(1.2 x 10-5 N) jhat
Office hours…MW 12:30-1:30 pm TR 9-10 am F 1-2 pm
Tutorial Learning Center (TLC) hours:??
Chapter 26
The Electric Field(E-Field Models & E-Field of
Multiple Point Charges)
The Electric Field is defined as…
The magnitude of the E-field of a pt. charge is…
Last time…
+
Permittivity constant.. Define a new constant..
so that…
Coulomb’s Law becomes…
Electric Fields & Superposition Q: @ P, what is the E-field?
P
q1
q2
q3
Electric Fields & Superposition Q: @ P, what is the E-field?
A: @ P,
P
q1
q2
q3
q3
q1
i.e. 26.1: The electric field of 3 equal pt. q’s
Three equal positive point charges q are located on the y-axis at y = 0 and at y = ±d. What is the electric field at a point on the x-axis?
q2
d
d
P
x
i.e. 26.1: The electric field of 3 equal pt. q’s
Three equal positive point charges q are located on the y-axis at y = 0 and at y = ±d. What is the electric field at a point on the x-axis?
q2
q3
q1
d
d
P
x
An Electric Dipole is… 2 equal but opposite charges separated by a small
distance.
Kinds: Permanent Electric Dipole (i.e. H2O) Induced Electric Dipole (i.e. polarized atom)
Dipole Moment…
The Electric Field of a Dipole
-q
+q
s
The Electric Field of a Dipole
Calculate the electric field of a dipole on the axis of the dipole…
-q
+q
sx
yP
The Electric Field of a Dipole
Calculate the electric field of a dipole on the axis of the dipole…
Notice: r is distance measured from the center of dipole.
-q
+q
sx
yP
The diagram shows a positive charge +q and a negative charge –q with the same magnitude. The electric field at point P on the plane that bisects the dipole is:
1. Up.2. Down.3. Left.4. Right.5. Zero.
Quiz Question 1
-q
+q
P
The Electric Field of a Dipole
Calculate the electric field of a dipole in the plane that bisects the dipole.
-q
+q
sx
y
The Electric Field of a Dipole
Calculate the electric field of a dipole in the plane that bisects the dipole.
sx
y
-q
+q
The Electric Field of a Dipole
Calculate the electric field of a dipole in the plane that bisects the dipole.
Notice: field is opposite to p & half the strength of on-axis field.
-q
+q
sx
y
