If the V= 5.6x3yz+7.5xy4, calculate the x-component of the electric field at point (6.9,6.9,13.36)

Review. In fair weather, the electric field in the air at a particular location immediately above the Earth's surface is 120 N/C directed downward, (a) What is the surface charge density on the ground? Is it positive or negative? (b) Imagine the surface charge density is uniform over the planet. What then is the charge of the whole surface of the Earth? (c) What is the Earths electric potential due to this charge? (d) What is the difference in potential between the head and the feet of a person 1.75 m tall? (Ignore any charges in the atmosphere.) (e) Imagine the Moon, with 27.3% of the radius of the Earth, had a charge 27.3% as large, with the same sign. Find the electric force the Earth would then exert on the Moon, (f) State how the answer to part (e) compares with the gravitational force the Earth exerts on the Moon.

Oppositely charged parallel plates are separated by 5.33 mm. A potential difference of 600. V exists between the plates. (a) What is the magnitude of the electric field between the plates? (b) What is the magnitude of the force on an electron between the plates? (c) How much work must be done on the electron to move it to the negative plate if it is initially positioned 2.90 mm from the positive plate?

In different experimental trials, an electron, a proton, or a doubly charged oxygen atom (O--), is fired within a vacuum tube. The particle's trajectory carries it through a point where the electric potential is 40.0 V and then through a point at a different potential. Rank each of the following cases according to the change in kinetic energy of the particle over this part of its flight from the largest increase to the largest decrease in kinetic energy. In your ranking, display any cases of equality, (a) An electron moves from 40.0 V to 60.0 V. (b) An electron moves front 40.0 V to 20.0 V. (c) A proton moves from 40.0 V to 20.0 V'. (d) A proton moves from 40.0 V to 10.0 V. (e) An O-- ion mines from 40.0 V to 60.0 V.

Unreasonable Results (a) A certain parallel plate capacitor has plates of area 4.00 m2 separated by 0.0100 mm of nylon, and stores 0.170 C of charge. What is the applied voltage? (b) What is unreasonable about this result? (c) Which assumptions are responsible or inconsistent?

(a) Find the electric potential difference Ve required to stop an electron (called a stopping potential) moving with an initial speed of 2.85 107 m/s. (b) Would a proton traveling at the same speed require a greater or lesser magnitude of electric potential difference? Explain. (c) Find a symbolic expression for the ratio of the proton stopping potential and the electron stopping potential. Vp/Ve.

In Figure 20. 1, two points and are located within a region in which there is an electric field. (i) How would you describe the potential difference V = V V? (a) It is positive. (b) It is negative. (c) It is zero. (ii) A negative charge is placed at and then moved to . How would you describe the change in potential energy of the chargefield system for this process? Choose from the same possibilities. Figure 20.1 (Quick Quiz 20.1) Two points in an electric field.

In a certain region of space, the electric potential is zero everywhere along the x axis. (i) From this information, you can conclude that the x component of the electric field in this region is (a) zero, (b) in the positive x direction, or (c) in the negative x direction. (ii) Suppose the electric potential is +2 V everywhere along the x axis. From the same choices, what can you conclude about the x component of the electric field now?

An electron is released from rest in a uniform electric field. Determine whether the following quantities increase, decrease, or remain unchanged as the electron moves. Indicate your answers with I (increase), D (decrease), or U (unchanged), respectively. (a) The electric potential at the electrons location (b) The electrons associated electric potential energy (c) Its kinetic energy (d) Its total energy.

A Review Consider the charged disks in Problem 72 (Fig. P26.72). Find an expression for the electric field at point A between the disks on the x axis. Approximate any square roots to three significant figures.