o 
o 
o 
o No correct answer
139. The potential energy associated with a pair of point charges separated by a distance r 12 is:
· 
o 
o 
o 
o No correct answer
140. The electric potential due to a continuous charge distribution is:
· 
o 
o 
o 
o No correct answer
141. The capacitance C of any capacitor is the ratio of the charge Q on either conductor to the potential difference ∆ V between them:
· 
o 
o 
o 
o No correct answer
142. The SI unit of capacitance is:
· C/V
o V/C
o C/V2
o C/V·m
o No correct answer
143. The equivalent capacitance of a parallel combination of capacitors is:
· Ceq=C1+C2+C3+...
o 1/Ceq=1/C1+1/C2+1/C3+...
o Ceq=C1=C2=C3=...
o Ceq=C1·C2·C3·...
o No correct answer
144. If two or more capacitors are connected in series, the equivalent capacitance of the series combination is given by:
o Ceq=C1+C2+C3+...
· 1/Ceq=1/C1+1/C2+1/C3+...
o Ceq=C1=C2=C3=...
o Ceq=C1·C2·C3·...
o No correct answer
145. The energy stored in a capacitor with charge Q is:
· 
o 
o 
o 
o No correct answer
146. The electric dipole moment p of an electric dipole has a magnitude:
· p=2aQ
o p=Q
o p=Q2
o p=-2aQ
o No correct answer
147. The torque acting on an electric dipole in a uniform electric field E is:
· τ = p x E
o τ = p · E
o τ = p / E
o τ =q p x E
o No correct answer
148. The potential energy of the system of an electric dipole in a uniform external electric field E is:
· U=- p · E
o U= p x E
o U= p · E
o No correct answer
o U= p / E
149. he electric current I in a conductor is defined as:
· 
o 
o 
o 
o No correct answer
150. The average current in a conductor is related to the motion of the charge carriers through the relationship:
· Iav=nqvdA
o Iav=nqvd
o Iav=qvdA
o Iav=nq/vdA
o No correct answer
151. The magnitude of the current density J in a conductor is:
· J=I/A
o J=IA
o J=IA2
o J=I2/A
o No correct answer
152. Ohm’s law in the differential form is:
· J =σ E
o I=U/R
o I=R/U
o J =σ/ E
o No correct answer
153. Ohm’s law in the integral form is:
o J =σ E
· I=U/R
o I=R/U
o J =σ/ E
o No correct answer
154. The resistance R of a conductor is defined as:
· R=∆V/I
o R =σ E
o R=∆V·I
o R=I/∆V
o No correct answer
155. For a uniform block of material of cross sectional area A and length l, the resistance over the length l is:
· 
o 
o 
o 
o No correct answer
156. The power supplied to the element, is:
· P=I∆V
o P=I/∆V
o P=I2∆V
o P=I∆V2
o No correct answer
157. The power delivered to a resistor can be defined as:
· P=I2R
o P=IR
o P=IR2
o P=I2/R
o No correct answer
158. The equivalent resistance of a set of resistors connected in series is:
· Req=R1+R2+R3+...
o 1/Req=1/R1+1/R2+1/R3+...
o Req=1/(R1+R2+R3+...)
o Req=R1+R2+R3+...
o No correct answer
159. The equivalent resistance of a set of resistors connected in parallel is found from the relationship:
o Req=R1+R2+R3+...
· 1/Req=1/R1+1/R2+1/R3+...
o Req=1/(R1+R2+R3+...)
o Req=R1+R2+R3+...
o No correct answer
160. Circuits involving more than one loop are conveniently analyzed with the use of Kirchhoff’s rules:
· 1. The sum of the currents entering any junction in an electric circuit must equal the sum of the currents leaving that junction. 2. The sum of the potential differences across all elements around any circuit loop must be zero.
o 1. The product of the currents entering any junction in an electric circuit must equal the sum of the currents leaving that junction. 2. The sum of the potential differences across all elements around any circuit loop must be constant.
o 1. The sum of the currents at any circuit loop must be zero. 2. The sum of the potential differences across all elements around any circuit loop must be zero.
o 1. The sum of the currents entering any junction in an electric circuit must equal the sum of the currents leaving that junction. 2. The product of the potential differences across all elements around any circuit loop must be zero.
o No correct answer
161. A parallel-plate capacitor with air between the plates has an area A =2.00·104 m2 and a plate separation d =1.00 mm. Find its capacitance.
· C=1.77 pF
o C=1.77 F
o C=1.77 mF
o C=1.77 nF
o No correct answer
162. Find the equivalent capacitance between a and b for the combination of capacitors shown in Figure. All capacitances are in microfarads. 
· 6.0 μF
o 6.0 F
o 5.0 μF
o 6.0 nF
o No correct answer
163. A parallel-plate capacitor has plates of dimensions 2.0 cm by 3.0 cm separated by a 1.0-mm thickness of paper. Find its capacitance (k = 3.7, ε0=8.85·10-12 C2/N·m2).
· 20 pF
o 20 F
o 40 pF
o 60 pF
164. Find the electric flux Φe though the spherical surface, covers the point-like charges q1=5 nC and q2=-2 nC. (ε0=8.85·10-12 C2/N·m2)
· Φe=339 N·m2/C
o Φe=0.339 N·m2/C
o Φe=339 N/C
o Φe=339 N·m2
o No correct answer
165. Find the attractive force F between nuclei of hydrogen atom and electron. Radius of hydrogen atom is r=0.5·10-10 m; modules charge of nuclei are equaland opposite to charge sign of electron (ε0=8.85·10-12 C2/N·m2).
· F=92.3·10-9 N
o F=92.3 N
o F=92.3·10-9 N/m2
o F=92.3·10-9 N
o No correct answer
166. Two point-like charges in air (ε=1) at the distance r1=20 sm from each other interact with some force. At what distance r2 one needs to place this charges in oil (ε2=5) to get the same force of interaction?
· r2=8.94 sm
o r2=8.94 m
o r2=8.94·103 m
o r2=8.94·10-3 m
o No correct answer
167. What times the gravitational force between two protons less the electrostatic force of their repulsion? The charge of proton is equal on module and opposite on sign of charge of electron.
· 
o 
o 
o 
o No correct answer
168. The electron and proton of a hydrogen atom are separated (on the average) by a distance of approximately 5.3·10-11 m. Find the magnitudes of the electric force between the two particles. (ke=8.99·109 N·m2/C2)
· 8.2·10-8 N
o 8.2 N
o 8.2·10-9 N
o 8.2·109 N
o No correct answer
169. Calculate the resistance of an aluminum cylinder that has a length of 10.0 cm and a cross-sectional area of 2.00·10-4 m2 (ρ=2.82·10-8 Ω·m).
· R= 1.4·10-5 Ω
o R= 1.4·10-3 Ω
o R= 1.4 Ω
o R= 1.4·105 Ω
o No correct answer
170. Calculate the resistance of an glass cylinder that has a length of 10.0 cm and a cross-sectional area of 2.00·10-4 m2 (ρ=3·1010 Ω·m).
· R= 1.5·1013 Ω
o R= 1.5·10-13 Ω
o R= 1.5·1013 Ω
o R= 1.5·103 Ω
o No correct answer
171. Calculate the resistance per unit length of a 22-gauge Nichrome wire, which has a radius of 0.321 mm (The resistivity of Nichrome is 1.5·10-6 Ω·m).
· 4.6 Ω/m
o 4.6 Ω
o 4.6 Ω·m
o 4.6·10-3 Ω/m
o No correct answer
172. If a potential difference of 10 V is maintained across a 1.0-m length of the Nichrome wire with resistance 4.6 Ω, what is the current in the wire?
· 2.2 A
o 0.46 A
o 2.2·10-3 A
o 0.46·103 A
o No correct answer
173. An electric heater is constructed by applying a potential difference of 120 V to a Nichrome wire that has a total resistance of 8.00 Ω. Find the current carried by the wire.
· 15 A
o 0.06 A
o 15·10-3 A
o 0.06·10-3 A
o No correct answer
174. An electric heater is constructed by applying a potential difference of 120 V to a Nichrome wire that has a total resistance of 8.00 Ω. Find the power rating of the heater.
· 1.8 kW
o 1.8 W
o 120 W
o 0.1 kW
o No correct answer
175. A battery has an emf of 12.0 V and an internal resistance of 0.05 Ω. Its terminals are connected to a load resistance of 3.00 Ω. Find the terminal voltage of the battery.
· 11.8 V
o 8.07 V
o 11.95 A
o All answers are correct
o No correct answer
176. Calculate the power delivered to the load resistor, if the current in the circuit is 3.93 A, the load resistance is 3.00 Ω.
· 46.3 W
o 11.79 W
o 35.37 W
o All answers are correct
o No correct answer
177. Calculate the power delivered to the internal resistance of the battery, if the current in the circuit is 3.93 A, the internal resistance of 0.05 Ω.
· 0.772 W
o 0.1965 W
o 0.01 W
o All answers are correct
o No correct answer
178. Four resistors are connected as shown in Figure. Find the equivalent resistance between points a and b. 
· 12 Ω
o 2.7 Ω
o 5.37 Ω
o All answers are correct
o No correct answer
179. Four resistors are connected as shown in Figure. Find the equivalent resistance between points b and c. 
· 2 Ω
o 0.5 Ω
o 9 Ω
o All answers are correct
o No correct answer
180. Four resistors are connected as shown in Figure. Find the equivalent resistance between points a and c.
· 14 Ω
o 2.5 Ω
o 4.7 Ω
o 3.2 Ω
o No correct answer
181. Three resistors are connected in parallel as shown in Figure. A potential difference of 18.0 V is maintained between points a and b. Find the current I1. 
· I1=6.00 A
o I1=3.00 A
o I1=2.00 A
o All answers are correct
o No correct answer
182. Three resistors are connected in parallel as shown in Figure. A potential difference of 18.0 V is maintained between points a and b. Find the current I2.
o I1=6.00 A
· I1=3.00 A
o I1=2.00 A
o All answers are correct
o No correct answer
183. Three resistors are connected in parallel as shown in Figure. A potential difference of 18.0 V is maintained between points a and b. Find the current I3.
o I1=6.00 A
o I1=3.00 A
· I1=2.00 A
o All answers are correct
o No correct answer
184. Three resistors are connected in parallel as shown in Figure. A potential difference of 18.0 V is maintained between points a and b. Calculate the power delivered to resistor R1. 
· P1=108 W
o P1=54 W
o P1=36 W
o All answers are correct
o No correct answer
185. Three resistors are connected in parallel as shown in Figure. A potential difference of 18.0 V is maintained between points a and b. Calculate the equivalent resistance of the circuit. 
· Req=1.64 Ω
o Req=0.61 Ω
o Req=18 Ω
o All answers are correct
o No correct answer
186. A single-loop circuit contains two resistors and two batteries, as shown in Figure. (Neglect the internal resistances of the batteries.) Find the current in the circuit. 
· I=-0.33 A
o I=0.33 A
o I=1 A
o I=-3 A
o No correct answer
187. Consider three point charges located at the corners of a right triangle as shown in Figure, where q 1 = q 3 = 5.0 μC, q 2 =-2.0 μC, and a = 0.10 m. Find the resultant force exerted on q 3. 
· F3 =(-1.1 i +7.9 j)N
o F3 =(7.9 i -1.1 j)N
o F3 =(1.1 i -7.9 j)N
o F3 =(1.1 i +7.9 j)N
o No correct answer
188. An electric dipole is defined as a positive charge q and a negative charge - q separated by a distance 2 a. For the dipole shown in Figure, find the electric field E at P due to the dipole, where P is a distance y» a from the origin. 
· 
o 
o 
o 
o No correct answer
189. A rod of length l has a uniform positive charge per unit length λ and a total charge Q. Calculate the electric field at a point P that is located along the long axis of the rod and a distance a from one end. 
· 
o 
o 
o 
o No correct answer
190. Calculate the ratio of the electrostatic to gravitational interaction forces between two electrons, between two protons. At what value of the specific charge q/m of a particle would these forces become equal (in their absolute values) in the case of interaction of identical particles? (γ=6.67·10-11 m3/(kg·s2), me=9·10-31kg, mp=1·10-27kg, ke=8.99·109 N·m2/ C2)
· 4·1042 (for electrons); 1·1036 (for proton); q/m=0.86·10-10 C/kg
o 4·1042 (for proton); 1·1036 (for electrons); q/m=0.86·10-10 C/kg
o 4·1045 (for proton); 1·1038 (for electrons); q/m=0.86·10-13 C/kg
o 4·1043 (for electrons); 1·1035 (for proton); q/m=0.86·10-11 C/kg
o No correct answer
191. Two positive charges q1 and q2 are located at the points with radius vectors r1 and r2. Find a negative charge q3 and a radius vector r3 of the points at which it has to be placed for the force acting on each of the three charges to be equal to zero.
· 
o 
o 
o 
o No correct answer
192. A point charge q is located at a distance l from an infinite conducting plane. Determine the surface density of charges induced on the plane as a function of separation r from the base of the perpendicular drown to the plane from the charge.
· 
o 
o 
o 
o No correct answer
193. A thin infinitely long thread carrying a charge λ per unit length is oriented parallel to the infinite conducting plane. The distance between the thread and the plane is equal to l. Find: a) the modulus of the vector of the force acting on a unit length of the thread; b) the distribution of surface charge density σ(x) over the plane, where x is the distance from the plane perpendicular to the conducting surface and passing through the thread.
· 
, 
o 
, 
o 
, 
o 
, 
o No correct answer
194. A thin wire ring of radius R carries a charge q. Find the magnitude of the electric field strength on the axis of the ring as a function of distance l from its centre.
· 
o 
o 
o 
o No correct answer
195. Find the currents I 1, I 2, and I 3 in the circuit shown in Figure. 
· I 1=2 A, I 2=-3 A, I 3=-1 A
o I 1=-2 A, I 2=3 A, I 3=1 A
o I 1=2 A, I 2=-3 A, I 3=-5 A
o I 1=3 A, I 2=2 A, I 3=1 A
o No correct answer
196. The water (H2O) molecule has an electric dipole moment of 6.3·10-30 C·m. A sample contains 1021 water molecules, with the dipole moments all oriented in the direction of an electric field of magnitude 2.5·105 N/C. How much work is required to rotate the dipoles from this orientation (θ=0°) to one in which all the moments are perpendicular to the field (θ=90°)?
o 1.6·10-24 J
· 1.6·10-3 J
o -1.6·10-3 J
o 1.6·10-25 J
o No correct answer
197. A ball is thrown upward. While the ball is in free fall, does its acceleration
o Increases
o Decreases
o Increases and then decreases
o Decreases and then increases
· Remain constant
198. After a ball is thrown upward and is in the air, its speed in all path
o Increases
o Decreases
o Increases and then decreases
· Decreases and then increases
o Remain the same
199. If vector B is added to vector A, which two of the following choices must be true in order for the resultant vector to be equal to zero?
· A nd B are parallel in the same direction and have same magnitude
o A and B are parallel in opposite directions, but have same magnitude
o A and B have the same magnitude
o A and B are perpendicular but have same magnitude
o None of them is right
200. A car moves along y-axes. In the figure, velocity of the car as a function of time is shown in three parts (I, II, III). Which statement is ALWAYS true? 
· Velocity is constant in part II
o A car drives backward in part I
o Velocity is negative in part III
o Velocity is negative in part I
201. What is the cross product of two vectors A and B, if the angle between them is 30 degree, and magnitudes are |A|=4, |B|=2
o 5.6
· 4
o 0
o 8
o 2.5
202. When a box rests on the floor, it is acted upon by the gravitational and the _________________ force.
o Centrifugal
o Acceleration
· Normal
o Inertia
o Friction
203. Motion is produced by
o all forces
· unbalanced forces
o balanced forces
o the absence of force
o none of them
204. Force is that agent which produces or tends to produce the __________.
o Speed in the body
· Acceleration in the body
o Constant velocity in the body
o Constant angular velocity in the body
205. A force of 3N acts perpendicularly to a force of 4N. Their resultant has magnitude of ______
o 1N
· 5N
o 7N
o 9N
o 25N
206. In inelastic collision between the two bodies __________.
· Only momentum of the system is conserved
o Only the kinetic Energy of the system is conserved
o Both the kinetic Energy and Momentum of the system remain the same
o Total energy is not conserved
207. Work done by a grass cutter is maximum when he pulls it __________.
o Making an angle 450 with the floor
· Making an angle 900 with the floor
o Along a line parallel to the floor
o Making an angle 600 with the floor
208. A man does the work if he ___________.
· Goes to fifth floor of the building
o Goes to fifth floor of the building and comes back to ground floor
o Remain on the ground floor
o Goes to the basement and comes back to ground floor
209. In elastic collision between the two bodies __________.
o Only momentum of the system is conserved
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