Problem 72-1    Source:  Example 23-2 - TIPLER, Paul - MOSCA, Gene -    Book: Física - Vol. 2 - 5ª Edição - Ed. LTC - 2006.

a) Calculate the electrical potential at a distance r = 0.529 x 10^-10m of a proton (This is the average distance between a proton and an electron in the hydrogen atom).

b) What is the potential electrical energy of the electron and proton at this separation distance?

Problem 72-2    Source:  Example 23-3 - TIPLER, Paul - MOSCA, Gene -    Book: Física - Vol. 2 - 5ª Edição - Ed. LTC - 2006.

Two point charges of +5 nC are on the axis x, one located at the origin and the other x = 8 cm , as shown in Figure 72-02.2. Determine:

a) the potential at point P₁ on the x axis in x = 4 cm.

b) the potential at point P₂ on the y axis in y = 6 cm.

Problema 72-3    Source:  Problem 29.3 - page 905 - KNIGHT, Randall D. -    Book: Física - Uma Abordagem Estratégica - 2ª Edição - Ed. Bookman - 2009.

A proton departs from the positive plate's rest in a parallel plate capacitor. It crosses the capacitor and reaches the negative plate with a speed of 50,000 m/s. What will be the final speed of the proton if the experiment is repeated with twice the amount of original charge on each capacitor plate.

Problem 72-4    Source:  Problem 2 - page 99 - HALIDAY & RESNICK -    Book: Fundamentos da Física - 8ª edition - Ed. LTC - 2009.

The difference in electrical potential between the Earth and a storm cloud is 1.2 x 10⁹ V. What is the magnitude of the change in electric potential energy of an electron moving from the cloud to Earth?

Problem 72-5    Source:  Problem 22.11 - page 18 - TIPLER, Paul - MOSCA, Gene -    Book: Física - Vol. 2 - 4ª Edição - Ed. LTC.

An electron enters a uniform electric field with E^→ = - 2,000   j^→ N/C and with initial speed v_o^→ = 10⁶   i^→ m/s perpendicular to the field.

a) compare the gravitational force acting on the electron to the electrical force in the field.

b) how much the electron will be deflected from the horizontal after advancing 1 cm in the direction x?

Problem 72-6    Source:  Problem elaborated by the author of the site.

Suppose an electron positioned at point A which is at a distance of 4 cm from a charged particle with + 2.0 nC. Find the work required to move the electron to a point B located 20 cm from the particle.

Problem 72-7    Source:  Problem elaborated by the author of the site.

Let two electric charges, A and B, be separated by a distance of d = 10 cm. If payload A is loaded with 12 µC and payload B with -5 µC, find the value of the potential at the midpoint of the line connecting the two charges.

Problem 72-8    Source:  Problem elaborated by the author of the site.

Consider two points, A and B, distant d_A = 8 cm and d _B = 25 cm, respectively, of a charge loaded with 120 µC. How much work must the electric field do to move a charge of -12 µC from point B to point A?

Problem 72-9    Source:  Problem elaborated by the author of the site.

Repeat problem 72-08 considering that we must shift a charge of + 12 µC from point B to point A.