Unformatted text preview: 12141 212149
Instructor: Profs. P. Avery, P. Kumar, Y. Lee
PHYSICS DEPARTMENT PHY 2054 Exam 1 February 4, 2009 ‘ _ M
Name (PRINT, last, ﬁrst): ﬂ Signature: 5: On my honor, I have neither given nor received unauthorized aid on this examination. YOUR TEST NUMBER IS THE 5DIGIT NUMBER AT THE TOP OF EACH PAGE. DIRECTIONS
1 Code your test number on your answer sheet (use 76—80 for the 5digit number). Code your name on your answer sheet. DARKEN CIRCLES COMPLETELY. Code your student number on your answer sheet. ( )
2 Print your name on this sheet and sign it also. Do all scratch work anywhere on this exam that you like. At the end of the test, this exam printout is to be turned in.
( )
( ) No credit will be given without both answer sheet and printout with scratch work most questions demand.
4 Blacken the circle of your intended answer completely, using a #2 pencil or blue or black ink. Do not make any stray marks or the answer sheet may not read properly.
5 The answers are rounded off. Choose the closest to exact. There is no penalty for guessing. >>>>>>>>WHEN YOU FINISH <<<<<<<<
Hand in the answer sheet seoaratel . so = 8.85 x 10—12 F/m me : 9.11 x 1031 kg m,, = m" = 1.67 x 1027 kg e = 1.6 x 1019 C k: = 9 x 109 N mz/C2 #0 = 12.56 x 10‘7 H/m NA = 6.02 x 1023 atoms/mole c = 3 x 108 m/s n...o=1.333 micro= 106
7, 1. Five identical charges of +1aC are located on the 5 vertices of a regular hexagon of
1 m side leaving one vertex empty. A elaC point charge is placed at the center of the
hexagon. Find the‘ magnitude and direction of the net Coulomb force on this charge. @ 9.0 x 10—3 N in the negative m—direction ® HM‘
(2) 4.5 x 10’3 N in the negative :cdirection
(3) 4.5 x 10—3 N in the negative ydirection
(4) 5.2 x 10‘3 N in the positive y—direction
(5) 9.0 x 10—3 N in the positive mdirection 2. Two small identical conducting balls, insulated from their surroundings and separated by a large distance, have charges
3.2aC and —1.4pC, respectively. The balls are then touchedjogether and then bmnghtiackjojheimgiginal Lositiqns.
If F1 is the magnitude of the force between the balls before corn—get and F2 is the magnitude of the force after contact, what is the ratio F2 / F1? ‘7‘ @ 1.0 (2) 5.5 « (3) 1.4 (4) 0.18 (5) 0.72 3. Three charges Q1 = —3[.LC, Q2 = ~6pC and Q3 = +9nC produce an electric ﬁeld of strength E at a point P. All 3
charges are now made 4 times larger. The new ﬁeld at P is ‘ > @ 4E (2) 2E (3) 3E (4) E (5) 16E
4. A 30V battery is connected to a circuit and the current delivered to the circuit falls linearly from 7 A to 2 A over 4
hours. How much charge (in kiloCoulombs) was delivered to EH; circuit by the battery? ’—' ‘— \— (1) 50 (2) 130 @65 (4) 430 (5) 29 5. A special room is set up so that there is a downward pointing electric ﬁeld of magnitude E. A ball of mass 4 kg and
charge 0.005 C is dropped from a height of 20.0 m? striking the ground 1.5 seconds later. What isﬁ (Don’t forget to include gravity, 9 = 9.8 m/s2.)
(1) 14200 V/m (2) 6380 V/m (3) 13500 V/In (4) 29170 V/m 9 22060 V/m ...
View
Full Document
 Spring '09
 DUNNAM

Click to edit the document details