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Quiz for Static Electricity
Name ________________________________
Date _____________
1. What property makes metals good conductor?
2. Is there a single correct reference point from which all electric potential energy
measurements must be taken?
3. Suppose you are asked to measure the electric field in the space. How can you
detect the field at a point?
4. In the experiment you did yesterday, what do you expect for the temperature
increase ΔT if you used one capacitor only while the potential difference or
voltage ΔP unchanged?
5. If the charge on a capacitor is changed, what is the effect on its capacitance C?
6. Suppose we have a large, hollow sphere that has been charged. Through a hole in
the sphere, we insert a small, uncharged sphere into the hollow interior and let
them touch. What is the charge on the small sphere?
7. A metal box is charged with high voltage so it is going to discharge. At what
point the discharge will occur (at corners or on the sides)?
8. If 120 J of work is performed to move one coulomb of charge from a point to
another point, what potential difference exists between the two points?
9. The electric field in the atmosphere is about 150 N/C. Find the electric force on a
proton with charge 1.6 x 10-19 C.
10. A 12 V battery does 1200 J of work transferring charge. How much charge is
transferred?
11. A capacitor that is connected to a 45 V source contains 90 μC of charge. What is
the capacitor’s capacitance?
12. The gap between electrodes in a spark plug is 0.6 mm. To produce an electric
spark in a gasoline-air mixture, there must be an electric field of 3 x 106 N/C.
What minimum potential difference must be supplied by the ignition circuit to
start a car?
13. A force of 0.053 N is required to move a charge of 37 μC a distance of 25 cm in
an electric field. What is the electric potential difference between the two points?
14. Find the potential difference between a point infinitely far away and a point 1.0
cm from a proton.
15. Find the intensity of electric field at a point midway between two charges of 40 x
10–9 C and 60 x 10-9 C separated by a distance of 0.3 m. The Coulomb constant is
9 x 109 N·m2/C2.