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Electric Fields and Potential Homework
 A test charge of 2 x 10^{8} C experiences a force of 0.06 N when
placed in an electric field. What is the electric field intensity? Ans:
3 x 10^{6}N/C
 A test charge of +5 x 10^{4} C is in an electric field which exerts a force
of 2.5 x 10^{4}N upon it. What is the strength of the electric
field? Ans: 0.5 N/C
 A test charge of +80 mC is placed in a
50 N/C field. What force does it experience? Ans: 0.004 N
 A +4.9 mC charge produces an electric
field of 3.6 x 10^{4} N/C upon a positive test charge. How far
away is the charge? Ans: 1.11 m
 A 19 mC charged sphere produces a 1.7 x 10^{
3} N/C upon a 0.5 mC test charge. What
force is the charge subjected to? How far away is the test charge from
the sphere? Ans: 0.00085 N; 10.03 m
 The electric field intensity between two parallel, charge plates is
8000 N/C. The plates are 0.05 m apart. What potential difference exists
between the plates? Ans: 400 V
 A spark will jump across dry air when the electric field is larger
than 1 x 10^{6} N/C. If two parallel plates have a potential
difference of 5000 V, how far apart must they be to prevent a spark from
jumping across them? Ans: 0.005 m
 What work is done on a 5 C charge when its electric potential is
increased by 1.5 V? Ans: 7.5 J

A charge of 50 C is raised in potential by 110 V. What work is done in
raising the potential of the charge? Ans: 5500 J
Capacitors and Oil Drop Homework
 An oil drop carries a charge of 5 electrons and is balanced in a
field of 4.7 x 10^{4} N/C. What is the drop's weight? Ans:
3.76 x 10^{14} N
 A negatively charged oil drop weighs 8.5 x 10^{15} N. The
drop is suspended in an electric field of 5300 N/C. What is the drop's
charge? How many excess electrons does it carry? Ans: 1.6 x 10^{
18} C; 10 electrons
 What is the charge on a 6mF capacitor with a
potential difference of 0.60 V? Ans: 3.6 mC
 A capacitor has a charge of 3 mC and a
potential difference of 45 V. What is its capacitance? Ans: 0.067
mF
 A 0.002 F capacitor has a 6 V potential difference across it. How much
energy does it store? Ans: 0.036 J
 A +26 C charged sphere is touched to a 19 C charged sphere and then
removed. What charge remains on each? Ans: +3.5 C
Electric
Field, Potential, and Capacitors Notes
Electric
Field, Potential, and Capacitors Sample Problems