Since in the
case
of both
figures
(the circle from the system and the
ellipse)
the
highest
value for
x
has the ordinate 0
(as
the 1st
differential
quotient shows),
and the centers of all circles lie
within
the
ellipse,
we
only
have to examine
whether
for
y
=
0
one
of
the two
points
of the circle lies outside the
ellipse.
Since the
entire
figure
under examination is symmetrical with respect to the
yaxis,
we
need to consider
only
one
(the
positive)
side.
[Note
in
margin:]
The
proof
is
not sound.
We
must make
a
direct
comparison
of the
equations
for the
circle
and
for the
ellipse
and
identify the
x
and
y
of both.
Ellipse
Ax2
+ y2
=
r2
I
Circle x2

2px
+
y2

r2
+
2p2
=
0
If
we
eliminate
y:
^ x2 
2px
+
2p2
=
0
x2

4px
+
4p2
=
4p2
+
4p2
The
expression 44p*
+
4p*
x
=
2
p
Substituted in I
2p2
+y2
=
r2
y
=
+
4
r*

2p*
.
For the root to be
real,
we
must have
r2
2p2
p
42
r
p
Ü
J
2
there is
no more
contact with the
ellipse.
r
If
p
,
/
2
24.
MATURA EXAMINATION (D) PHYSICS: "TANGENT
GALVANOMETER AND
GALVANOMETER"
[19 September
1896, 2:303:45
P.M.]
Albert Einstein
TANGENT GALVANOMETER AND GALVANOMETER.
Each electric current is surrounded
by circular, concentric
magnetic lines
of force that lie in
planes perpendicular
to
the
18