PHYS 112 Midterm: PHYS 112 Iowa State Exam1 S15
Document Summary
Spring 2015: three identical negative point charges (q = 4. 0 c) are fixed in a vertical line, 10 cm apart. What is the net electric force on the bottom charge marked with a (*): 18 n down, 22 n down, 34 n up, 16 n up, 0 n. Q: the top of a van de graff is a spherical conducting shell (radius = 15 cm) with a net negative charge of 20 c. Estimate the magnitude of the electric field 20 cm from the shell, as shown: 2. 9 103 n/c, 8. 0 104 n/c, 4. 5 105 n/c, 6. 0 105 n/c, 1. 5 106 n/c. Shell, 20 c: two positive particles of charge, + 16 c and + 4 c are some distance apart, as shown. In which region or point (a-e), on a line connecting the charges, is e = 0? (point c is mid-way between the charges)
