SP212/3321&5521
Chapter 28 - Worksheet #2
Question 1: (HRW Question 28.7) The figure below shows the path of an electron that passes through
two regions containing uniform magnetic fields of magnitudes B1 and B2 . Its path in each region is
a half-circle. (a) Which field is stronger? (b) What is the direction of each field? (c) Is the time
~ 1 region greater than, less than, or the same as the time spent in the
spent by the electron in the B
~ 2 region?
B
Question 2: A point particle with mass 2.0 × 10−9 kg and charge −3.5 × 10−6 C is travelling at a
constant speed of 1500 m/s in a circle of radius 3.5 m, moving clockwise when viewed from above.
What is the magnetic field in this region? Answer both magnitude and direction.
−3.5 µC
−
1500 m/s
y
3.5 m
x
+z is out of the page
SP212/3321&5521
Chapter 28 - Worksheet #2
Question 3: (HRW Checkpoint 28.3) The figure here shows the circular paths of two particles that
~ which is directed into the page. One particle
travel at the same speed in a uniform magnetic field B,
is a proton; the other is an electron (which is less massive). (a) Which particle follows the smaller
circle, and (b) does that particle travel clockwise or counterclockwise? (c) The shown circles are not
actually to scale. What should be the ratio of the radius of the larger circle to that of the smaller
circle? (The masses of both the electron and proton are listed on your equation sheet.)
Question 4: A charged particle with mass 4.5 × 10−9 kg travelling at a constant speed of 3300 m/s
in a circle of radius 2.2 m, moving clockwise when viewed from above, in a region with a uniform
~
magnetic field of B=(5.75
T)k̂. (a) What si the particle’s charge? (b) How long does it take for this
particle to make one full revolution around the circle? (i.e. What is its period?)
3300 m/s
5.75 T
2.2 m