1. Norah Ali Al-moneef king saud university
4/11/2017
Norah Ali Al-moneef king saud university

2. Norah Ali Al-moneef king saud university
4/11/2017
Norah Ali Al-moneef king saud university

3. Norah Ali Al-moneef king saud university
4/11/2017
Norah Ali Al-moneef king saud university

4. Norah Ali Al-moneef king saud universityP q1 q2 q3 q4
What is the potential at point P, located at the center of the square of point charges. Assume that d = 1.3m and the charges are
q1 = +12 n C, q2= -24 n C
q3 = +31 n C, q4= +17 n C
4/11/2017
Norah Ali Al-moneef king saud university

5. Norah Ali Al-moneef king saud university
Two point charges each of magnitude 2.00 μC are located on the x axis. One is at x = 1.00 m, and the other is at x = ‑1.00 m. a) Determine the electric potential on the y axis at y = m. b) Calculate the change in electric potential energy of the system as a third charge of –3.00 μC is brought from infinitely far away to a position on the y axis at y = m.
4/11/2017
Norah Ali Al-moneef king saud university

6. Norah Ali Al-moneef king saud university
A proton is moved from the negative plate to the positive plate of a parallel-plate arrangement. The plates are 1.5cm apart, and the electric field is uniform with a magnitude of 1500N/C.
How much work would be required to move a proton from the negative to the positive plate?
What is the potential difference between the plates?
If the proton is released from rest at the positive plate, what speed will it have just before it hits the negative plate?
4/11/2017
Norah Ali Al-moneef king saud university

7. Norah Ali Al-moneef king saud university
A uniform electric field of magnitude 290 V/m is directed in the positive x direction. A µC charge moves from the origin to the point (x, y) = (20.0 cm, 50.0 cm).(a) What is the change in the potential energy of the charge field system?
4/11/2017
Norah Ali Al-moneef king saud university

8. Gain or loss?
A negative charge gains electric potential energy when it moves in the direction of the electric field. Explain this.
A proton loses potential energy when moving in the direction of the electric field, but picks up an equal amount of kinetic energy.
Work done by a field is positive when energy is given to an object from the field (object is lowered in a gravitational field or moved in the direction of E filed lines). This occurs when Uf <Ui so, W=-ΔU

9. Norah Ali Al-moneef king saud university
1- The electric field has a magnitude of 3.0 N/m at a distance of 60 cm from a point charge. What is the charge?
(a) 1.4 nC
(b) 120 pC
(c) 36 mC
(d) 12 C
(e) 3.0 nC
4/11/2017
Norah Ali Al-moneef king saud university

10. The gap between electrodes in a spark plug is 0
The gap between electrodes in a spark plug is 0.06cm, To produce an electric spark in a gasoline air mixture, an E field of 3x106V/m must be achieved. When starting the car, what minimum potential difference must be supplied by the ignition circuit?

11. Calculate the speed of a proton that is accelerated from rest through a potential difference of 120V. An electron?

12. An ion accelerated through a potential difference of 115V experiences an increase in kinetic energy of 7.37x10-17 J. Calculate the charge of the ion

13. How much work is done in moving Avogadro's number of electrons from an initial point where the electric potential is 9V to a point where the potential is -5V?

14. Compute the energy necessary to bring together the charges in the configuration shown below:
Calculate the electric potential energy between each pair of charges and add them together.

15. What is the electric potential at the point
i) 10 cm and
ii) 50 cm from a point charge of 2 µC ?
Find the work done to move a charge of 0.05 µC from
a point 50 cm from the point charge 2 µC to a point 10 cm
from the point charge. State whether the work done by
or on the electric field. a) b)
Work done on the electric field.

16. Norah Ali Al-moneef king saud university
Two point charges, 8x10-9 C and -2x10-9 C are separated by 4 m. The electric field magnitude (in units of V/m) midway between them is:
9x B) 13, C) 135,000 D) 36x E) 22.5
4/11/2017
Norah Ali Al-moneef king saud university