This preview shows pages 1–2. Sign up to view the full content.
Quiz 9 Phys. 2306 F09
You may use your text book, notes, and a calculator.
Three inﬁnitely long wires run from
∞ ≤
z
≤ ∞
and carry currents of mag
nitude I. The current in wire 1 that passes through the point (x,y)
=
(0,a) ﬂows
in the +z direction, the current in the wire 2 that passes through the point
(x,y)
=
(0,a) ﬂows in the z direction, and the current in wire 3 that passes
through the point (x,y)
=
(b,0) ﬂows in the z direction.
1) What is the direction of the magnetic ﬁeld at wire 3?
a) +x b) x c) +y d) y e) none of these
Choose the x,y,z axes i
,
j
,
k in the following directions: right, up, out of pa
per. Wires 1 and 2 are both a distance
d
=
√
a
2
+
b
2
from wire 3. Thus the
ﬁelds at wire 3 have equal magnitudes,
B
=
μ
0
I
2
πd
. However, they point in diﬀerent
directions. The directions of the ﬁeld lines from each wire are concentric circles
about wires 1 and 2. So draw a circle of radius
d
with centers at wire 1 and 2
and where the circles intersect wire 3 draw the tangents in the correct sense.
For wire 1, B
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview. Sign up
to
access the rest of the document.
This note was uploaded on 12/24/2011 for the course PHYS 2306 taught by Professor Ykim during the Fall '06 term at Virginia Tech.
 Fall '06
 YKim
 Current

Click to edit the document details