Unit 8 Quiz#1
Part 1: FIll in the Blank
1. A neutral object becomes ________________ charged if electrons are removed.
2. Unlike charges _______________ one another.
3. _______________ are materials with a conductive capacity between conductors and insulators.
4. The process of charging a neutral body by touching it with a charged body is called charging by ________________.
5. Charges added to a(n) _______________ will immediately spread throughout the body.
6. Charges added to one part of a ________________ will remain in that part.
Part 2: Multiple Choice
Choose the one best answer to the following questions. (1 pt. each)
1. Two like charges ________.
2. Protons and electrons ____________.
3. The electrical force between charges is strongest when the charges are __________.
4. If you comb your hair and the comb becomes positively charged, then your hair becomes __________.
5. A conductor differs from an insulator in that a conductor ________.
6. A negatively charged rod is brought near a metal can that rests on a wood table. You touch the opposite side of the can momentarily with your finger. The can is then _______.
7. An electroscope is charged positively as shown by foil leaves that stand apart. As a negative charge is brought close to the electroscope, the leaves _________.
8. Two charges separated by one meter exert a one N force on each other. If the charges are pulled to 3 m separation distance, the force on each charge will be ________.
9. Two charges separated by one meter exert a one N force on each other. If the magnitude of each charge is doubled, the force on each charge is _________.
10. A positive charge and a negative charge held near each other are released. As they move, the force on each particle __________.
Part 3: Problem-Solving
To receive credit for the following problems, show some work.
1. A hydrogen atom contains a proton and an elctron separated by a distance of 5.0 x10-11 meters. The charge on the proton is the same as the charge on the electron: 1.6x10-19 C. Calculate the force of attraction between the two particles.
2. A positve charge of 1.8x10-6 C and a negative charge of -1.0x10-6 C are 0.014 m apart. What is the force between the two particles?
3. Two charged objects have a repulsive force of .020 N. If the charge of one of the objects is doubled, then what is the new force?
4. Two charged objects have a repulsive force of .04 N. If the distance separating the objects is halved, then what is the new force?
5. Two charged objects have an attractive force of .02 N. If the charge of one of the objects is halved, and the distance separating the objects is doubled, then what is the new force?
6. Two charged objects have a repulsive force of .020 N. If the charge of both of the objects is doubled and the distance separating the objects is doubled, then what is the new force?
Part 4: Correcting False Statements
The following statements are false. In three complete sentences or less, explain what is wrong with the statement and correct it.
1. Object A is positively charged and Object B is electrically neutral. When object A touches Object B, protons are transferred from Object A to Object B.
2. If an electroscope is touched by a charged object, the leaves will diverge. However, when the object is drawn away, the leaves will relax to their original rest position.
3. Object A is positively charged. Object B is an electrically neutral insulator. If Object A is brought near to Object B, the electrons in Object B travel to the surface which is nearest to Object A.
4. The leaves of a positively charged electroscope are separated. If a physics student, standing on the ground, touches the electroscope with a plastic baseball bat, then the electroscope will be discharged and the leaves will relax to their original rest position.
5. The leaves of a positively charged electroscope are separated. When the electroscope is touched by a person standing upon the ground, the positive charges within the electroscope will be transmitted through the person and into the earth.
Part 5: Short Answer
Using three complete sentences or less, answer three of the following questions.
1. Distinguish between a conductor and an insulator.
2. Distinguish between a positively charged object and a negatively charged object.
3. Distinguish between charging by contact and charging by conduction.
4. Explain how an electrically neutral object can be attracted to a charged body.
5. How can you charge an object negatively with only the help of a positively charged object?
© Tom Henderson, 1996-1998
Last updated on