Download PracticeQuiz F&E

Quiz Side (Solution on other side)
PHYSICS 102
QUIZ: Force & Electric Field
Wtr 2007
!!! SHOW YOUR WORK AND EXPLAIN YOUR REASONING !!!
1. Two charged objects, q1 and q2, are fixed at the locations given below:
q1: -3 x 10-5 C located at y = 3 meters
q2: +6 x 10-5 C located at y = 0 meters
Draw a diagram of the situation in the box. Include the
charges and the coordinate axes.
a) Draw a vector representing the Force on q1 by q2 and
label it F1. (1 pt)
b) Draw a vector representing the Force on q2 by q1 and
label it F2. (1 pt)
c) Find the magnitude of F1. (Don’t forget units!) (3 pts)
d) Find the Electric Field at the position y=4 m due to
q2. Give magnitude and direction. (2 pts)
e) How many electron’s were added to q2 to result in the given charge? (Hint: Think
unit conversion!) (2 pts)
2. The electric field has been mapped in a small region. A
field map (with electric field lines) is shown. (1 pt)
y
a) Show the force direction on an electron placed at
the position marked with an "x."
b) Show the force direction on a proton placed at the
position marked with an "y."
x
Solution Side
1. Two charged objects, q1 and q2, are fixed at the locations given below:
q1: -3 x 10-5 C located at y = 3 meters
q2: +6 x 10-5 C located at y = 0 meters
Draw a diagram of the situation in the box. Include the
charges and the coordinate axes.
F1
a) Draw a vector representing the Force on q1 by q2 and
label it F1. (1 pt)
b) Draw a vector representing the Force on q2 by q1 and
label it F2. (1 pt)
F2
c) Find the magnitude of F1. (Don’t forget units!) (3 pts)
8.99 10
3 10
6 10
3
d) Find the Electric Field at the position y=4 m due to q2. Give magnitude and
direction. (2 pts)
6 10
8.99 10
4
e) How many electron’s were added/removed to/from q2 to result in the given
charge? (Hint: Think unit conversion!) (2 pts)
6 10
1
1.6 10
2. The electric field has been mapped in a small region. A
field map (with electric field lines) is shown. (1 pt)
y
a) Show the force direction on an electron placed at
the position marked with an "x."
c) Show the force direction on a proton placed at
the position marked with an "y."
kq q
Handy Info.! F = 12 2
r
N⋅m
k = 8.99 × 10
C2
9
2
x
e = 1.6 × 10−19 C