Unit 6 Quiz 1 Practice Questions

1. When a plastic rod is rubbed with wool, the wool acquires a positive charge because
electrons are transferred from the wool to the rod
protons are transferred from the wool to the rod
electrons are transferred from the rod to the wool
protons are transferred from the rod to the wool

2. Conductivity in metallic solids is due to the presence of free
nuclei protons neutrons electrons

3. If a positively charged rod is brought near the knob of an uncharged electroscope without
touching it, the leaves will diverge because
negative charges are transferred from the electrocope to the rod
negative charges are attracted to the knob of the electroscope
positive charges are repelled to the leaves of the electroscope
positive charges are transferred from the rod to the electroscope

4. When a positively charged body touches a neutral body, the neutral body will
gain protons lose protons gain electrons lose electrons

5. If object A becomes positively charged when rubbed with object B, then object B has
gained electrons lost electrons gained protons lost protons

6. Why does a neutral hard rubber rod become negatively charged when rubbed with wool ?
The rod loses protons The rod loses electrons The wool loses protons The wool loses electrons

7. When two objects are rubbed together, which particle is most likely to be tranferred ?
nucleus electron proton neutron

8. A neutral object can become positively charged by
gaining electrons losing electrons gaining protons losing protons

9. As a negatively charged rod is moved toward the tip of a positively charged electroscope,
the number of electrons in the tip of the electroscope
decreases increases remains the same

10. As charged body A charges neutral body B by direct contact, the quantity of charge on body A
is decreased is increased remains the same

11. In general, solid materials become electrically charged because of transfer of
positrons electrons protons neutrons

12. A neutral pith ball suspended on a string is attracted to a positively charged rod. During contact
with the rod, the pith ball
loses electrons gains electrons loses protons gains protons

13. If a positively charged rod touches a neutral metal sphere, the number of electrons on the rod will
decrease increase remain the same

14. A positively charged rod is held near, but does not touch the knob of a neutral electroscope.
The charge on the knob becomes
positive and the leaves become positive
positive and the leaves become negative
negative and the leaves become positive
negative and the leaves become negative

15. When two neutral materials are rubbed together, there is a transfer of electrical charge from
one material to the other. The total electrical charge for the system
increases as electrons are transferred
increases as protons are transferred
remains constant as protons are transferred
remains constant as electrons are transferred

16. If the distance between two protons is tripled, then the force they exert on each other, compared
to the original force, will be
one-ninth as great one-third as great three times as great nine times as great

17. If the distance between two point sources of equal charge is halved, the electrical force between
the sources will be
halved doubled quartered quadrupled

18. Two point charges that are separated by a distance of 1.0 m repel each other with a force equal
to 9.0 N. What is the force of repulsion when these two charges are 3.0 m apart ?
1.0 N 27 N 3.0 N 81 N

19. If the charge on one of two positively charged spheres is doubled, the electrostatic force of
repulsion between the spheres will be
halved doubled quartered quadrupled

20. If a negatively charged object has an excess of 2.5 x 1019 electrons, its net charge is
-1.6 C -2.5 C -6.5 C -4.0 C

21. A rod and a piece of cloth are rubbed together. If the rod acquires a charge of +1 x 10-6 C, the
cloth acquires a charge of
0 C +1 x 10-6 C -1 x 10-6 C +1 x 106 C

22. The electrostatic force of attraction between two small spheres that are 1.0 m apart is F. If the
distance between the spheres is decreased to 0.5 m, the electrostatic force will then be
F/2 2F F/4 4F

23. A sphere has a negative charge of 6.4 x 10-7 C. Approximately how many electrons must be
removed to make the sphere neutral ?
1.6 x 10-8 9.8 x 105 6.4 x 1026 4.0 x 1012

24. A metal sphere with a charge of +11 elementary charges touches an identical sphere with
a charge of +15 elementary charges. After the spheres touch, the charge on the first sphere is
+13 +26 -4 +4

25. A and B are two identical uncharged metal spheres. Sphere A is given an electrical charge
of +q, touched to sphere B, and then removed. The charge on sphere A after separation is
+q -q +q/2 -q/2

Base your answers to questions 26 and 27 on the diagram below.

U6Q3Image2.gif (2987 bytes)


26. If an electron moves from point A to point B, the electron's electric potential energy will
decrease increase remain the same

27. If an electron moves from point A to point C, the electron's electric potential energy will
decrease increase remain the same

28. The diagram below represents a positive test charge located near a positively charged sphere.

U6Q3Image2.gif (2987 bytes)


The greatest increase in the electric potential energy of the test charge would be caused by moving the charge to
point A point B point C point D

29. The diagram below represents a system consisting of two charged metal spheres with equal radii.

U6Q3Image3.gif (4025 bytes)

Compared to the electrical PE of the system at a separation of 12 m, the electrical PE at a separation of 6 m is
less greater the same

30. A volt is defined as a
J/C J/s C/s J.s/C

31. A proton moves through a potential difference of 1000 V. The change in the proton's potential energy will be
1000 eV 2000 eV 3000 eV 4000 eV

32. How much energy is required to move 3.2 x 10-19 C of charge through a potential difference of 5 volts ?
5 eV 2 eV 10 eV 20eV

33. An oil drop has a charge of -4.8 x 10-19 C. How many excess electrons does the oil drop have ?
1.6 x 10-19 2.0 3.0 6.3 x 1018

34. How much energy is needed to move one electron through a potential difference of 100 volts ?
1.0 J 100 J 1.6 x 10-19 J 1.6 x 10-17 J

35. Moving a point charge of 3.2 x 10-19 C between points A and B in an electric field requires 4.8 x 10-19 J of
energy. What is the potential difference between these two points ?
0.67 V 2.0 V 3.0 V 1.5 V

36. The work required to move a charge of 0.04 C from one point to another in an electric field is 200 J.
What is the potential difference between these two points ?
5000 V 2 x 10-4 V 8 V 200 V

37. The energy of an electron may be increased by 8 x 10-17 J if it is moved through a potential difference of
0.002 V 200 V 500 V 5000 V

38. An object carrying a charge of -2 x 10-6 C is acted upon by an electric force of 0.06 N. The
magnitude of the electric field intensity at this point is
3 x 104 N/C 3 x 10-5 N/C 1 x 102 N/C 3 x 103 N/C

39. A charged particle is placed in an electric field E. If the charge on the particle is doubled, the
force exerted on the particle by the field E is
unchanged doubled halved quadrupled