From @JohnDenker: In figure 24.27 on page 656, in the second column
("electric field geometry") the word "uniform" is used
three times in three consecutive sentences ... with three
different meanings.
What's worse, in all three cases the word is uninformative,
in the following sense: If the student already understands
the field geometry, then he says "OK, I guess that's what
'uniform' means in this context" ... but if he doesn't
already know, the word won't help him figure it out.
My suggestion: Remove the word from this figure entirely,
and instead spell out the intended meaning in each case:
a) The magnitude of the field is independent of θ and φ
in spherical polar coordinates. The direction is
everywhere radially outward from the center, in the
direction of increasing r.
b) The magnitude of the field is independent of θ and z
in cylindrical coordinates. The direction is radially
outward from the axis, in the direction of increasing ρ.
c) The magnitude of the field is independent of position.
The direction is independent of x and y, and "almost"
independent of z; it depends only on z/|z|, i.e. it
points away from the plane on both sides.
From @JohnDenker: In figure 24.27 on page 656, in the second column ("electric field geometry") the word "uniform" is used three times in three consecutive sentences ... with three different meanings.
What's worse, in all three cases the word is uninformative, in the following sense: If the student already understands the field geometry, then he says "OK, I guess that's what 'uniform' means in this context" ... but if he doesn't already know, the word won't help him figure it out.
My suggestion: Remove the word from this figure entirely, and instead spell out the intended meaning in each case:
a) The magnitude of the field is independent of θ and φ in spherical polar coordinates. The direction is everywhere radially outward from the center, in the direction of increasing r.
b) The magnitude of the field is independent of θ and z in cylindrical coordinates. The direction is radially outward from the axis, in the direction of increasing ρ.
c) The magnitude of the field is independent of position. The direction is independent of x and y, and "almost" independent of z; it depends only on z/|z|, i.e. it points away from the plane on both sides.