Ch 22 Practice Pr soln

Ch 22 Practice Pr soln - Chapter 22 Practice Pr solns 16 W...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 22 Practice Pr solns: 16. The potential difference and the work per unit charge, done by an external agent, are equal in magnitude, so (50 C)(12 V) 600 J. W q V μ = ∆ = = ( Note: Since only magnitudes are needed in this problem, we omitted the subscripts A and B .) 17. D EVELOP We assume that the electron is initially at rest. When released from the negative plate, it moves toward the positive plate, and the kinetic energy gained is | | . U q V = E VALUATE As the electron moves from the negative side to the positive side (i.e., against the direction of the electric field), the kinetic energy it gains is 19 17 |( ) | 120 eV (1.6 10 C)(120 V) 1.92 10 J K e V - - = - = = × = × A SSESS Moving a negative charge through a positive potential difference is like going downhill; potential energy decreases. However, the kinetic energy of the electron is increased. 18. The work done by an external agent equals the potential energy change, 45 J , AB AB U q V = = hence AB V = 45 J/15 mC 3 kV. = (Since the work required to move the charge from A to B is positive, and B A AB V V V is positive.) 19. I NTERPRET This problem is about conversion of units. D EVELOP By definition, 1 volt 1 joule/coulomb = (1 V 1 J/C). = On the other hand, 1 joule 1 newton-meter = (1 J 1 N m). = E VALUATE Combining the two expressions gives 1 V 1 J/C 1 N m/C. = = It follows that 1 V/m 1 N/C. = A SSESS These are the units for the electric field strength. 20.
Background image of page 1

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

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 3

Ch 22 Practice Pr soln - Chapter 22 Practice Pr solns 16 W...

This preview shows document pages 1 - 2. Sign up to view the full document.

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