Download ELECTRIC FIELDS all type

ELECTRIC FIELDS – All Types
(Recall, 1 elementary charge =  1.60 x 10 –19 C
1. In a certain region of space, a force of 3.5 N is
exerted upon a body of 1.80 x 10 –19 C charge.
What is the magnitude of the electric field at that
point in space?
2. An electron, which carries 1 elementary unit of charge is in an electric field and
experiences a force of 7.00 x 10 –16 N. Find the magnitude of the electric field at that
location.
3. A body whose charge is 5.00 x 10 –5 C is subjected to an electrical force of 0.0300 N.
a) What is the electrical field at this point?
b) If this first body is removed, and replaced by a second body, this second body
experiences a force of 1.80 x 10 –15 N. What is the charge on this second body?
How many units of elementary charge is this?
4. If a charge of 5.20 x 10 –7 C is placed in an electric field where the field intensity is
2.50 x 10 5 N/C, what will be the magnitude of the force acting on the charge?
5. Suppose the electric field between the plates is 2.50 x 10 5 N/C. What force would be
exerted upon the following if they were put between the plates?
a) Al 3+ ion
b) O 2- ion
(Hint: 1 elementary charge = 1.60 x 10 –19C)
6. What is the magnitude of the force exerted on an electron in an electric field of 600
N/C?
7. An oil droplet is suspended in mid air above a charged plate. The field strength at the
point where the droplet is 85 N/C. The charge on the droplet is estimated to be 3 elch.
What is the mass of the oil droplet?
8. A student is using a Millikan apparatus and finds the following:
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- an oil droplet of mass 1.8 x 10 kg suspended above a charged plate.
- the electric field is found to be 2.7 N/C at the point of the droplet.
Find the charge of the droplet in elementary charges.
9. An oil droplet of radius 0.0003 cm is located in a Millikan’s apparatus. It is suspended
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in mid air above a 0.45 N/C electric field. The density of oil is 800 kg/m . Determine the
charge of the droplet in Coulombs.
10. An oil droplet of diameter 0.0003 cm is located in a Millikan’s apparatus. It is
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suspended in mid air above a 0.30 N/C electric field. The density of oil is 800 kg/m .
Determine the charge of the droplet in elementary charges.
11. An oil droplet of diameter .008 cm is located in a Millikan’s apparatus. It is
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suspended in mid air above an electric field. The density of oil is 800 kg/m . If the oil
droplet is found to have a charge of 4 elch, determine the field strength at the point in
space where the drop is.
Answers
1. 1.94 x 1019 N/C
2. 4.375 x 103 N/C
3. 600 N/C
b) 19 electrons
4. 0.13 N
5. 1.2 x 10-13 N b) 8 x 10-14 N
6. 9.6 x 10-17 N
7. 4.08 x 10-17 N
m = 4.163 x 10-18 kg
8. 4.074 x 109 elch
9. q = 1.97 x 10-12 C
10. 2.31 x 106 elch
11. 3.284 x 109 N/C