Question

7. Determine the ratio of the electrostatic force to the gravitational force betwen a poton and an electron, FE/FO. Note: k-899 x 10° N㎡C; G=6672x ir'i N rAg. m,=9.109×10-34 kg; and n-1.672 x 10"kg. A) 124 x 103 B) 2.52× 1029 C) 1.15 x 10" D) 2.26 x 10 E) 142 x 10 8. In the figure, point A is a distance I away from a point charge @. Point B is a distance 4 away from Q. What ís the ratio ofthe electric field at B to th-at A. Eti 1/16 A 2 C) 1/4 D) 1/3 E) This cannot be determined since neither the value of O nor the length L is specified. E R 3L+L 9. Asmall sphere of mass 2.5 x lors kg carnes atotal charge of 60 ×10" C. The sphere hangs from a silk thread between two large parallel conducting plates. The excess charge on each plate is equal in magnitude, but opposite in sign. If the thead makes an angle of 30 with the positive plate as shown, what is the magnitude of the charge density on each plate A) 2.5 x 10 C/m B) 5.2x 10 C/m ト、1 C) 10x 10 C/m D) 2.1 x 10- C/m E) 4.2 x 10 Cm 3-

Answer 1

7. Here we shall use Coulomb's Law and Newton's Gravitational Law to determine the ratio of the magnitude of the Electrostatic force to that of the Gravitational force between an electron and a proton.