Taller de Electróstatica TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false. 1) A neutron carries a negative charge. 1) 2) The coulomb, which is the unit of charge, is the charge on one electron. 2) 3) Electric charge is quantized. 3) 4) A positive charge placed in an electric field experiences a force in the direction of the field. 4) 5) If a conductor is placed in an electric field under electrostatic conditions, the electric field is excluded from the inside of the conductor. 5) MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 6) Electrons carry a 6) A) negative charge. B) neutral charge. C) variable charge. D) positive charge. 7) When an electron is removed from a neutral atom, it becomes 7) A) a positive ion. B) a negative ion. C) more massive. D) a bipolar atom. E) heavier. 8) Sphere A carries a net charge and sphere B is neutral. They are placed near each other on an insulated table. Which statement best describes the electrostatic force between them? A) The force is attractive if A is charged positively and repulsive if A is charged negatively. B) There is a force of attraction between them. C) There is a force of repulsion between them. D) There is no force between them since one is neutral. E) The force is repulsive if A is charged positively and attractive if A is charged negatively. 9) In electricity, what quantity is analogous to the "acceleration of gravity" g (which is a force per unit mass)? A) electric charge B) electric force C) electric field D) electric potential E) an electric dipole 8) 9) 10) Electric field lines 10) A) were invented by Isaac Newton. B) are closer together the stronger the field. C) start on negative charges and end on positive charges. D) were discovered by Franklin. E) are perpendicular to the lines of force.
FIGURE 15-2 11) Which of the arrows shown in Fig. 15-2 represents the correct direction of the electric field between the two metal plates? A) A B) B C) C D) D 11) FIGURE 15-3 12) The electric field shown in Fig. 15-3 12) A) increases down. B) increases to the right. C) decreases down. D) decreases to the right. E) is uniform. 13) Gaussian surfaces A and B enclose the same positive charge +Q. The area of Gaussian surface A is three times larger than that of Gaussian surface B. The flux of electric field through Gaussian surface A is A) three times larger than the flux of electric field through Gaussian surface B. B) three times smaller than the flux of electric field through Gaussian surface B. C) nine times larger than the flux of electric field through Gaussian surface B. D) unrelated to the flux of electric field through Gaussian surface B. E) equal to the flux of electric field through Gaussian surface B. 13) 14) The charge carried by one electron is e = -1.6 10-19 C. The number of electrons necessary to produce a charge of -1.0 C is A) 1.6 1019. B) 1.6 109. C) 6.3 109. D) 6.3 1018. 14)
15) A piece of plastic has a net charge of +2.00 µc. How many more protons than electrons does this piece of plastic have? A) 2.50 1013 B) 1.25 1019 C) 0 D) 2.50 1019 E) 1.25 1013 16) The force of attraction between a -40.0 µc and +108 µc charge is 4.00 N. What is the separation between these two charges? A) 2.49 m B) 1.13 m C) 3.67 m D) 3.12 m E) 2.10 m 15) 16) FIGURE 15-7 17) As shown in Fig. 15-7, a point charge of +Q is placed at the center of a square, and a second point charge of -Q is placed at the upper-left corner. It is observed that an electrostatic force of 2 N acts on the positive charge at the center. What is the magnitude of the force that acts on the center charge if a third charge of -Q is placed at the lower-left corner? A) 2 2 N B) 4 N C) zero D) 2/ 3 N 17) FIGURE 15-1 18) As shown in Fig. 15-1, a point charge of +Q is placed at the centroid of an equilateral triangle. When a second charge of +Q is placed at one of the triangle's vertices, an electrostatic force of 4.0 N acts on it. What is the magnitude of the force that acts on the center charge due to a third charge of +Q placed at one of the other vertices? A) 8.0 N B) zero C) 2.0 N D) 4.0 N E) 16 N 18)
FIGURE 15-8 19) Fig. 15-8 shows electric field lines near two electric point charges. If Q1 = -1 µc, what is the value of Q2? A) -2 µc B) 0 C) +1 µc D) +2 µc E) -1 µc 19) TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false. 20) Negative charges, when released, accelerate toward regions of lower electric potential. 20) 21) Electric potential decreases when moving farther from positive charges or nearer to negative charges. 21) 22) The capacitance of a parallel plate capacitor is directly proportional to its plate separation. 22) 23) A capacitor, in addition to storing charge, also stores electrical energy. 23) MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 24) The absolute potential at the center of a square is 3. V when a charge of +Q is located at one of the square's corners. What is the absolute potential at the square's center when a second charge of -Q is placed at one of the remaining corners? A) -12 V B) 12 V C) -6 V D) 6 V E) zero 24) 25) For a proton moving in the direction of the electric field 25) A) its potential energy increases and its electric potential increases. B) both its potential energy and it electric potential remain constant. C) its potential energy decreases and its electric potential increases. D) its potential energy increases and its electric potential decreases. E) its potential energy decreases and its electric potential decreases. 26) Capacitance of capacitors depends upon 26) A) the space between the conductors. B) the geometry of the conductors. C) the material between the conductors. D) all of these answers. E) none of these answers. 27) Which of the following will increase the capacitance of a parallel plate capacitor? 27) A) an increase in the plate area and a decrease in the plate separation B) an increase in the potential difference between the plates C) a decrease in the plate area and an increase in the plate separation D) a decrease in the potential difference between the plates
28) When two or more capacitors are connected in parallel to a battery, 28) A) each capacitor carries the same amount of charge. B) the equivalent capacitance of the combination is less than the capacitance of any one of the capacitors. C) the voltage across each capacitor is the same. D) all of the given answers E) none of the given answers FIGURE 16-1 29) Fig. 16-1 shows three capacitors connected to a battery. The capacitances are such that C1 = 2C2 and C1 = 3C3. Which capacitor stores the smallest amount of charge? A) All three capacitors store the same amount of charge. B) C1 C) C3 D) C2 E) C2 or C3 29) FIGURE 16-2 30) Three capacitors C1, C2, and C3 are connected to a battery as shown in Fig. 16-2. The three capacitors have equal capacitances. Which capacitor stores the most potential energy? A) C2 B) C3 C) C1 D) C2 or C3. They store the same amount of energy E) All three capacitors store the same amount of energy. 30)