Physics 060 Electric current worksheetMarch 13, 2008

1) Is it possible for two negative charges to attract each other? 1) _______ A) No, they will never attract. B) Yes, they will attract if one carries a larger charge than the other. C) Yes, they will attract if they are close enough. D) Yes, they always attract.

2) A glass rod is rubbed with a piece of silk. During the process the glass rod acquires apositive charge and the silk 2) _______ A) could either be positively charged or negatively charged. It depends on how hard the rod was rubbed. B) remains neutral. C) acquires a positive charge also. D) acquires a negative charge.

3) A proton carries a 3) _______ A) negative charge. B) positive charge. C) neutral charge. D) variable charge.

4) The model of the atom shows a 4) _______ A) nucleus consisting of both protons and neutrons, surrounded by a cloud of electrons. B) neutrally charged nucleus surrounded by both protons and electrons. C) nucleus consisting of both electrons and neutrons, surrounded by a cloud of protons. D) nucleus consisting of both protons and electrons, surrounded by a cloud of neutrons

5) A neutral atom always has 5) _______ A) the same number of neutrons as protons. B) more protons than electrons. C) the same number of protons as electrons. D) more neutrons than protons.

6) An atom has more electrons than protons. The atom is 6) _______ A) a superconductor. B) a negative ion. C) a positive ion. D) impossible.

7) Materials in which the electrons are bound very tightly to the nuclei are referred to as 7) _______ A) semiconductors. B) conductors. C) superconductors. D) insulators.

8) Materials in which the electrons are bound very loosely to the nuclei and can move about freely within the material are referred to as 8) _______ A) semiconductors. B) insulators. C) conductors. D) superconductors.

9) The charge carried by one electron is e = -1.6 × 10-19 C. The number of electrons necessary to produce a charge of -1.0 C is 9) _______ A) 6.25 × 109. B) 1.6 × 1019. C) 6.25 × 1018. D) none of the given answers

10) A piece of plastic has a net charge of +2.00 μC. How many more protons than electrons does this piece of plastic have? 10) ______ A) 1.25 × 1013 B) 2.50 × 1019 C) 2.50 × 1013 D) 1.25 × 1019

11) The total amount of charge that passes through a wire's full cross section at any point per unit of time is referred to as 11) ______ A) wattage. B) voltage. C) electric potential. D) current.

12) A coulomb per second is the same as 12) ______ A) a volt per second. B) a watt. C) a volt-second. D) an ampere.

13) The direction of convention current is taken to be the direction that 13) ______ A) positive charges would flow. B) negative charges would flow.

14) What current is flowing if 0.67 C of charge pass a point in 0.30 s? 14) ______ A) 2.2 A B) 0.30 A C) 0.67 A D) 0.20 A

15) How much charge must pass by a point in 10 s for the current to be 0.50 A? 15) ______ A) 5.0 C B) 0.050 C C) 20 C D) 2.0 C

16) A total of 2.0 × 1013 protons pass a given point in 15 s. What is the current? 16) ______ A) 1.3 mA B) 0.21 μA C) 3.2 μA D) 1.3 A

17) If 3.0 × 1015 electrons flow through a section of a wire of diameter 2.0 mm in 4.0 s, what is the current in the wire? 17) ______ A) 7.5 × 1014 A B) 7.5 × 107 A C) 0.24 mA D) 0.12 mA

18) A coffee maker, which draws 13.5 A of current, has been left on for 10 min. What is the net number of electrons that have passed through the coffee maker? 18) ______ A) 5.1 × 1022 B) 1.8 × 103 C) 1.5 × 1022 D) 8.1 × 103

1) A

2) D

3) B

4) A

5) C

6) B

7) D

8) C

9) C

10) A

11) D

12) D

13) A

14) A

15) A

16) B

17) D

18) A