A proton is initially at rest. After some time, a uniform electric field is turned on and the proton accelerates. The magnitude of the electric field is 1.81  105 N/C. (a) What is the speed of the proton after it has traveled 7.00 cm?   (b) What is the speed of the proton after it has traveled 70.0 cm?

Find an expression for the magnitude of the electric field at point A mid-way between the two rings of radius R shown in Figure P24.30. The ring on the left has a uniform charge q1 and the ring on the right has a uniform charge q2. The rings are separated by distance d. Assume the positive x axis points to the right, through the center of the rings. FIGURE P24.30 Problems 30 and 31.

An electron with a speed of 3.00 106 m/s moves into a uniform electric field of magnitude 1.00 103 N/C. The field lines are parallel to the electrons velocity and pointing in the same direction as the velocity. How far does the electron travel before it is brought to rest? (a) 2.56 cm (b) 5.12 cm (c) 11.2 cm (d) 3.34 m (e) 4.24 m

A point charge of 4.00 nC is located at (0, 1.00) m. What is the x component of the electric field due to the point charge at (4.00, 2.00) m? (a) 1.15 N/C (b) 0.864 N/C (c) 1.44 N/C (d) 1.15 N/C (e) 0.864 N/C

An electron and a proton, each starting from rest, are accelerated by the same uniform electric field of 200 N/C. Determine the distance and time for each particle to acquire a kinetic energy of 3.21016 J.

A thin conducing plate 2.0 m on a side is given a total charge of 10.0C . (a) What is the electric field 1.0 cm above the plate? (b) What is the force on an electron at this point? (c) Repeat these calculations for a point 2.0 cm above the plate. (d) When the electron moves from 1.0 to 2.0 cm above the plate, how much work is done on it by the electric field?

One end of a light spring with force constant k = 125 N/m is attached to a wall, and the other end to a metal block with charge qA = 2.00 C on a horizontal, frictionless table (Fig. P23.34). A second block with charge qB = 3.60 C is brought close to the first block. The spring stretches as the blocks attract each other so that at equilibrium, the blocks are separated by a distance d = 12.0 cm. What is the displacement x of the spring? Figure P23.34

Is it possible for a conducting sphere of radius 0.10 m to hold a charge of 4.0 C in air? The minimum field required to break down air and turn it into a conductor is 3.0 106 N/C.

A proton is released from rest at the origin in a uniform electric field in the positive x direction with magnitude 850 N/C. What is the change in the electric potential energy of the protonfield system when the proton travels to x = 2.50 m? (a) 3.40 1016 J (b) 3.40 1016 J (c) 2.50 1016 J (d) 2.50 1016 J (e) 1.60 1019 J

A Figure P23.65 shows two identical conducting spheres, each with charge q, suspended from light strings of length L. If the equilibrium angle the strings make with the vertical is , what is the mass m of the spheres? Figure P23.65