Homework 01-solutions - carroll (arc2632) Homework 01 yao...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: carroll (arc2632) Homework 01 yao (92945) 1 This print-out should have 21 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points Two uncharged metal balls, Z and X , stand on insulating glass rods. A third ball, carrying a negative charge, is brought near the ball X as shown in the figure. A conducting wire is then run between Z and X and then removed. Finally the third ball is removed. X Z conducting wire When all this is finished 1. balls Z and X are still uncharged. 2. ball Z is negative and ball X is neutral. 3. ball Z is neutral and ball X is negative. 4. balls Z and X are both negative. 5. balls Z and X are both positive, but ball X carries more charge than ball Z . 6. ball Z is negative and ball X is positive. correct 7. ball Z is positive and ball X is negative. 8. balls Z and X are both positive, but ball Z carries more charge than ball X . 9. ball Z is positive and ball X is neutral. 10. ball Z is neutral and ball X is positive. Explanation: When the conducting wire is run between Z and X , some negative charge flows from X to Z under the influence of the negative charge of the third ball. Therefore, after the wire is removed, Z is charged negative and X is charged positive. 002 10.0 points A strong lightning bolt transfers about 26 C to Earth. How many electrons are transferred? The charge on an electron is 1 . 60218 10- 19 C. Correct answer: 1 . 62279 10 20 . Explanation: Let : q = 26 C and q e = 1 . 60218 10- 19 C . The charge is proportional to the number of electrons, so q = n | q e | n = q | q e | = 26 C | 1 . 60218 10- 19 C | = 1 . 62279 10 20 . 003 10.0 points Two identical positive charges exert a repul- sive force of 6 . 1 10- 9 N when separated by a distance 3 . 8 10- 10 m. Calculate the charge of each. The Coulomb constant is 8 . 98755 10 9 N m 2 / C 2 . Correct answer: 3 . 1306 10- 19 C. Explanation: Let : F = 6 . 1 10- 9 N , d = 3 . 8 10- 10 m , and k e = 8 . 98755 10 9 N m 2 / C 2 . The electric force is F e = k e q 1 q 2 d 2 d 2 F e k e = q 2 q = radicalBigg d 2 F k e = d radicalbigg F e k e carroll (arc2632) Homework 01 yao (92945) 2 = (3 . 8 10- 10 m) radicalBigg 6 . 1 10- 9 N 8 . 98755 10 9 N m 2 / C 2 = 3 . 1306 10- 19 C . 004 10.0 points Object A and object B are initially uncharged and are separated by a distance of 1 meter. Suppose 10,000 electrons are removed from object A and placed on object B, creating an attractive force between A and B. An addi- tional 10,000 electrons are removed from A and placed on B and the objects are moved so that the distance between them increases to 2 meters....
View Full Document

This note was uploaded on 07/11/2011 for the course PHYS 302L taught by Professor Tsoi during the Spring '10 term at University of Texas at Austin.

Page1 / 10

Homework 01-solutions - carroll (arc2632) Homework 01 yao...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online