Download ) i! ,,.,,,.

Period:
Date:
Exam Review Sheet for Electrostatics and Electric Fields
Name:
FE = kqlqÿr2
e = 1,6 x 10-is C
k = 9 x 109 Nm2/C2
E= F/q
1 C = 6.24 x 1018 e
E= kq/r2
1. Explain what is meant by the terms below AND draw a picture to show each.
"Charging by Conduction",
"Polarization"
"Charging by Induction"
2. Explain what the Law of Conservation of Charge means.
,
Give the value of the elementary electric charge, What does this number represent?
t,ÿ,ÿ y',,ÿ"
°
' !<7
"l ÿ,.::" ÿ,.,ÿ,,ÿ?,,. 'I.
..'.ÿ ;' ..,ÿ' ÿ' " ÿ,. .. ..< ÿ' ÿ, 'ÿ+)ÿ,," 1.,;,'ÿ"/'''ÿ/''' /'/J ;',+f
Describe the electric charge distribution on the dome of a Van de Graff generator and explain why the charge resides
on the outside of the dome. What happens when a neutral object touches the Van de Graft? Think about the demos
in class.
, , /
),
l, ;/L
fi,ÿ,,;i'/
[1ÿ' D ;/ÿ+"
.': , '
I
,
A negatively charged object has a total electric charge of 2,375 C.
A) Does the object have an excess or deficiency of elections?
/
)
i!
,,.,,,.
B) Determine the number of excess or deficit electrons on the object. [1.484 x 10aÿ electrons]
),
.
Two objects are charged to -8 pC (1pC = 10-6 C). If the two objects are separated by a distance of 30 cm, what is the
electric force acting on one of the spheres? [6.4 N]
t; ,;ÿ
,
Answer the following three questions about Electric Fields:
A) Explain an electric field, a test charge, and how a "test charge" is used to determine the direction of an electric
"
< h °1
71"ÿ'ÿ,[ It,+< ,ÿ',<+7 77 :ÿ" ÿ' 7ÿ"f(V b(ÿ,"'k<;,ÿ
B) Discuss electric field intensity as it relates to distance from a chargecl bbject aÿd the density of field lines. ....
,,f
+..',!<' 7.,f,
?'A<. ,.of+" .-,',
C) Draw pictures to represent how field lines would be drawn around a positive charge and a negative charge.
?
8. Object i has a charge of 4.8 x 10-7 C. Object i is placed some distance from Object 2, which is also charged and
produces an electric field.
A) The further Object i is placed from Object 2, would the magnitude of the electric field increase, decrease, or stay
constant? Would the magnitude of the electric force increase, decrease, or stay constant?
v
(."zÿ)
27
J)
...... .......
.................... ÿ
'ÿ sÿ,ÿ.ÿ'ÿ .-,iÿ ÿ..ÿ.:ÿ,.,....,..
='................
'lf',' ,/'vÿ.l),,
jJ
rT::ÿ
s'ÿ7
'7!+
•{,,.,
i !< f"
ÿ,,ÿ,ÿ'/
/,"ÿ-ÿ ÿ.'."ÿ'"
it
°, / ÿ
l, " ÿf 1'
;., ,. ,,,ÿ+ Iÿ- , .,,<,+ÿ,+..,.
B) If Object i is experiencing an electric force of 1.5 Newtons at a certain distance, what is the magnitude of the
electric field at that point? [3.13 x 10o NIC]
>./C,ÿ) ÿ¢..
C) Why was it not necessary to know the charge on Object 2 to calculate part B?
.
What is the magnitude of the force a 1.5 x 10-6 C charge exerts on a 3.2 x 104 C charge that is located 1.5 m away?
[1.9 N]
10.
Point B is located 3 m away from a positive charge as seen below. What is the magnitude and direction of the
electric field at B if the magnitude of the positive charge is 4.5 x 10ÿ C?
I-ÿ ¢, o .ÿ ; ,I i ÿ, ¢.-
@
,
.
ti
)
ki,,+
<:7,
iL, I g It..." d_
"
13. Two charge spheres, 2 cm apart, repel each other with a force of 2x10-8 N. Determine the magnitude of the charge
on each if one has double the charge of the other.
..... _..- - = > ......
P
ii o,. "7'
14. Two charges have a force of 60 N between them. What will be the new force if...7
The distance is halved
One charge is doubled, the other halved
The distance is doubled
If one charge is doubled, distance is halved
For the following questions, make sure to draw the field lines all the way to the edge of the box.
15. A positively charged sphere (4 C) is placed near a second, negatively charged sphere (-12 C). Draw an electric field
diagram that represents the two charges in the box below.
16. Two positive charges and a negative charge are located as shown below. They each have the same magnitude of
charge. Draw the field diagram in the box below.
17. A positive ion iscalled a(an) Cÿ'E(- lÿ,t .... and a negative ion iscalled a(an) t;ÿ,'ÿ lO°'ÿ
18. If you comb your hair and the comb becomes positively charged, your hair becomes ÿ ,ÿ
19. In a good insulator, electrons are usually
°7 ÿ l,ÿ </
- hÿz'/4;ÿ'/ ÿ-iÿ) / •
20. How many electrons would be required to have a total charge of 5.25 C on a sphere?
>ÿ
. ÿ
..............
h,,ÿ..
.
.......................................
-%,
ÿ ÿ /'ÿ
< / <'/ ÿ
..... ÿ0ÿ <)'J
•
G '.;ÿ;0
.2 x 10-9 N.
21. Two charged spheres; 3.0 cm apart, attract each other with a force of
Determine the magnitude of the
charge on qÿ if q2 has a charge of 1.24 x 10ÿC.
< ,
-
4
#
,ÿ 7.,h, ;+s
22. What is the magnitude of the force that a +1.75 x 10-6 C charge exe slon a -2,2 x 10-4 C charge located 3.5 m away?
Is it an attractive or repulsive force?
. ,ÿ
<
.ÿ:
,,< ........
ÿ, 7<'' i?/ ÿ+')
,
% ' <k
Y
/
,,,7ÿ ÿ.,
. ?¢ÿ
.....
ÿ
ÿ, U ,t
') ÿ.
ÿ. ,
, ÿ,,ÿ,