Name: Class: Date: Exam 1--PHYS 202--Spring 2013 Multiple Choice Identify the choice that best completes the statement or answers the question 1 A metallic object holds a charge of 38 10 6 C What total number of electrons does this represent? a 24 10 13 b 16 10 14 c 61 10 13 d 42 10 14 2 Which of these statements is true about charging by induction? a it can not be done to conductors b it can only occur with protons c it does not require contact between two charged objects d it causes a bigger charge than charge by conduction 3 Which of the following best characterizes electrical insulators? a electric charges move freely within the material b they are good heat conductors c they have a high tensile strength d charges in the material don't move 4 Two charges, +Q and Q, are located two meters apart and there is a point along the line that is equidistant from the two charges as indicated Which vector best represents the direction of the electric field at that point? a Vector E A b Vector E B c Vector E C d The electric field at that point is zero 1
Name: 5 Two point charges are 4 cm apart They are moved to a new separation of 2 cm By what factor does the resulting mutual force between them change? a 2 b 1/2 c 1/4 d 4 6 In this figure, a negative charge, which is initially travelling in the +y direction, enters an electric field The charge curves to the left, as shown by the arrow in the figure What is the direction of the electric field that causes this motion a -x d +z b +x e +y c -y 7 Electric field is dimensionally equivalent to which of the following? a N m 2 /C 2 b N/C 2 c N/C d N m/c 2
Name: 8 This figure shows two charges and their electric field lines If the charge on the right has a magnitude of 10 µc, what is the sign and magnitude of the left charge? a -4 µc d -10 µc b -25 µc e +6 µc c +10 µc 9 Consider this configuration of charges Which vector best represents the net force acting on the bottom charge? a a d d b b e e c c 3
Name: 10 Consider this circuit All three capacitors are identical What is the voltage across C 1? C 2 C 1 C 3 12 V a 12 V c 6 V b 4 V d 8 V 11 This diagram shows a collection of charges At which point is the potential equal to zero? a a d d b b e e c c 4
Name: 12 At what point is the potential greatest? a A c both the same b B d it depends on the magnitude of the charge 13 Two pieces of copper wire are the same diameter The length of wire A is twice that of wire B How do their resistances compare? a R A =R B d R A =2R B b R A =½R B e R A =4R B c R A =¼R B 14 When you apply a potential of 3 V to a particular electrical device, the current in 2 A When you apply 6V, the current is 4 A Is this device Ohmic or Non-Ohmic? a Ohmic c Neither b Non-Ohmic d Not enough information 15 Which of these has the greater current, a incandescent light bulb (60 W) or a bathroom heater (1000 W)? a bulb c heater b both the same 5
Name: Problem 16 (20 pts) Consider the following circuit Find the equivalent capacitance and the voltage and charge on each capacitor C eq = V 1 = Q 1 = V 2 = Q 2 = V 3 = Q 3 = V 4 = Q 4 = V 5 = Q 5 = 6
Name: 17 (20 pts) a) What is the electric field in vector notation at the point (x=10, y=10) meters if the electric potential is given by V=2yx 2 3y, where V is in volts and x & y are in meters? b) An electron is placed at the point ( 10 i + 10 j) and then released What is the velocity, in vector notation, of the electron after t=1x10-5 s? (Assume that the electric field remains constant as the electron moves) 7
Name: 18 (10 pts) Consider this circuit and answer the following questions: b) What is the voltage for each resistor? V 1 = V 2 = b) What is the resistance for each resistor? R 1 = R 1 = c) What is the current for each resistor? I 1 = I 2 = 8
Name: 19 (20 pts) Two charges are arranged on the vertices of this equilateral triangle as shown a) What is the potential at the top of the triangle (where the smiley face is)? b) How much work is required to place a charge of 3µC at the top of the triangle (where the smiley face is)? 9
ID: A Exam 1--PHYS 202--Spring 2013 Answer Section MULTIPLE CHOICE 1 ANS: A PTS: 1 2 ANS: C PTS: 1 3 ANS: D PTS: 1 4 ANS: A PTS: 1 DIF: 2 TOP: 154 The Electric Field 5 ANS: D PTS: 1 6 ANS: B PTS: 1 7 ANS: C PTS: 1 DIF: 1 TOP: 154 The Electric Field 8 ANS: A PTS: 1 9 ANS: B PTS: 1 10 ANS: D PTS: 1 11 ANS: B PTS: 1 12 ANS: A PTS: 1 13 ANS: D PTS: 1 14 ANS: A PTS: 1 15 ANS: C PTS: 1 PROBLEM 16 ANS: PTS: 1 17 ANS: PTS: 1 18 ANS: PTS: 1 19 ANS: PTS: 1 1