Question
The maximum score for each problem, is shown in parentheses next to the question number Use the value of 9 × 109 Nm 2/C2 for the Coulomb constant k in Coulomb's force law The magnitude of the charge of an electron is 1.6 × 10-19 c. The mass of an electron is 9 × 10-31 Kg. The mass of a proton is 1.7×10-27Kg Acceleration due to gravity is 9.8 m/sec2 PHYS 2426: Class test, Oct 12, 2017 · * · * . Question (2) A proton is moving along the positive X-axis in a uniform electric field with E =-16 × 105N/C. (a) what is the acceleration vector of the proton? (b) if the initial speed of the proton is 104 meters/sec, how far will the proton travel before coming to a stop? 1. (3) A solid sphere of radius 10cm carries a charge of 20 x 10-9 C that is uniformly distributed across its volume. What is the electric field magnitude at a distance of (a) 5cm, (b) 10cm, (c) 20 cm from the center of the sphere? [Caution: be careful about units] (3) Determine the magnitude of the electric field at the surface of a Carbon-12 nucleus, whi 3. ch contains 6 protons. Assume the volume of the nucleus is 12 times that of a single proton whose radius is 1.2 × 10-15m. You can assume that the Carbon nucleus is a uniformly charged sphere (3) Three closed surfaces S, through S, together with some point charges (+Q.-20. +30) are shown in the figure below (the curved lines are the intersection of the surfaces with the plane of 4. the paper). Find the electric flux through each surface S3 +a +3 S2 (4) Calculate the electric field vector at the center O' of a uniformly charged semicircular rod of radius R with total charge Q. 5.
Explanation / Answer
1. (A) a = F/ m = q E / m
a = (1.6 x 10^-19)(-6 x 10^5 i )/ (1.7 x 10^-27)
a = - 5.65 x 10^13 m/s^2 i
(B) vf = v0 + a t
0 = 10^4 - (5.65 x 10^13)t
t = 1.78 x 10^-10 sec
