Calculate the proton’s angular frequency.
What is the magnetic field in that region of

space? Answer in units of T.
Serway CP 19 31
29:04, trigonometry, numeric,
>
1 min.
064

A singly charged positive ion has a mass
of 2
.
5
£
10
°
26
kg.
After being accelerated
through a potential di
Æ
erence of 250 V, the
ion enters a magnetic field of 0
.
5 T, in a direc-
tion perpendicular to the field.
Find the radius of the ion’s path in the field.

Serway CP 19 32
29:04, trigonometry, numeric,
>
1 min.
065
A
mass
spectrometer
is
used
to
examine
the isotopes of uranium.
Ions in the beam
emerge from the velocity selector at a speed
of 300000 m
/
s and enter a uniform magnetic
field of 0
.
6 T directed perpendicularly to the
velocity of the ions.
What is the distance between the impact

points formed on the photographic plate by
singly charged ions of
235
U
and
238
U
? Answer
in units of cm.
Serway CP 19 33
29:04, trigonometry, numeric,
>
1 min.
066
An electron moves in a circular path perpen-
dicular to a constant magnetic field of magni-
tude 1 mT.
If the angular momentum of the electron
about the center of the circle is 4
£
10
°
25
J
·
s,
find the radius of the circular path.
Answer

Chapter 29, section 4, Motion of a Charged Particle in a Magnetic Field
49
in units of cm.
067
Find the speed of the electron.
Answer in
units of m
/
s.
Serway CP 19 55
29:04, trigonometry, numeric,
>
1 min.
068
Two species of singly charged positive ions of
masses 2
£
10
°
26
kg ions 2
.
34
£
10
°
26
kg enter
a magnetic field at the same location with a
speed of 100000 m
/
s.
If the strength of the field is 0
.
2 T, and the
ions move perpendicularly to the field, find
their distance of separation after they com-
plete one half of their circular path. Answer
in units of cm.
Serway CP 19 59
29:04, trigonometry, numeric,
>
1 min.
069
Given:
g
= 9
.
8 m
/
s
2
.
A 1 kg metal ball having net charge 5
μ
C
is thrown out of a window horizontally at a
speed 20 m
/
s.
The window is at a height
20 m above the ground. A uniform horizontal
magnetic field of magnitude 0
.
01 T is perpen-
dicular to the plane of the ball’s trajectory.
Find the magnitude of the magnetic force
acting on the ball just before it hits the
ground. Ignore magnetic force in finding the
ball’s final velocity. Answer in units of N.
Spiral Motion
29:04, trigonometry, multiple choice,
>
1 min.
070
Neglect the e
Æ
ect due to gravity.
A uniform magnetic field is directed out of
the page.
A charged particle moves in the
plane of the page following a clockwise spiral
of increasing radius as shown.
B
B
A reasonable explanation is
1.
the charge is positive and speeding up.