# CH 24 Problems Electric Potential JH Given E

CH 24. Problems Electric Potential JH

Given: E and displacement, Required: work, Potential Diff Work = displacement times force (if uniform; o. w. integrate): = q*E*d = 6 e-13 J, Potential difference: -w/q = -3. 75 e 7 V

Suggested Problems

Answer: (a) 2. 4 x 104 V/m = 24 k. V/m ; (b) 2. 9 x 103 V = 2. 9 k. V Note: Electric potential is some alternative form of Electric field. However, it is a scalar unlike the vector E which make it easier to compute. You have to know how to go between E and V

Answer: (a) 30 V ; (b) 40 V ; (c) 5. 5 m

Answer: (a) -4. 5 x 103 V = -4. 5 k. V ; (b) same as (a) Note: A and B are lying in equal potential surfaces. You can move in many paths between A and B and potential difference remains the same.

21. The ammonia molecule NH 3 has a permanent electric dipole moment equal to 1. 47 D, where 1 D = 1 debye unit = 3. 34 x 10 -30 C. m. Calculate the electric potential due to an ammonia molecule at a point 52. 0 nm away along the axis of the dipole. (Set V = 0 at infinity. ) Answer: 1. 63 x 10 -5 V = 16. 3 micro. V Note: the potential from dipole drops like 1/r^2 and is proportional to the dipole moment rather than charge.

Answer: (a) 39 V/m ; (b) Toward plate 1 Note: Plate 1 and 2: he means from left to right as in the conventional direction starting always from left. Therefore, plate 1 is at left (-i).

Answer: (a) 0. 225 J ; (b) a. A = 45. 0 m/s 2 and a. B = 22. 5 m/s 2 ; (c) v. A = 7. 75 m/s and v. B = 3. 87 m/s

Answer: (a) 1. 2 x 104 V/m = 12 k. V/m ; (b) 1. 8 x 103 V = 1. 8 k. V ; (c) 0. 058 m = 5. 8 cm

- Slides: 24