Name Student ID Multiple Choice Questions Clearly circle the letter of your choice You do not need to show your work No points will be given to questions with two or more choices marked No partial credit will be given 3 points each 1 Two identical bar magnets are placed as shown Where is the net magnetic field zero a C b B c D d A 2 A positive charge is released from rest in E and B fields Both fields point along the x axis Which of the following statements regarding the charge s motion are correct a The charge will travel in a circle in the x y plane b The charge will remain at rest c The charge will travel along a straight line along the y axis d The charge will travel along a straight line along the x axis 3 The force on a charged particle created by its motion in a magnetic field is maximum at what angle between the particle velocity and field a 45 b zero c 180 d 90 4 A circular loop carrying a current of 1 0 A is oriented in a magnetic field of 0 35 T The loop has an area of 0 24 m2 and is mounted on an axis perpendicular to the magnetic field which allows the loop to rotate What is the torque on the loop when its plane is oriented at a 25 angle to the field a 0 01 N m b 0 076 N m c 0 051 N m 5 An RL series circuit has the following components 5 0 mH coil 1 0 ammeter and switch What is the time constant of this circuit a 200 s c 12 10 3 s b 2 5 d 5 0 d 4 6 N m resistor 12 V battery 10 2 s 10 3 s 6 A coil with a self inductance of 0 75 mH experiences a constant current buildup from zero to 10 A in 0 25 s What is the induced emf during this interval a 0 019 V b 0 045 V c 0 030 V d 0 47 V Name Student ID 7 A series RLC circuit in a radio is in resonance with AM 600 kHz If the radio station is changed to AM 1 200 kHz by what factor must the capacitance be multiplied to achieve resonance again Please note The inductor is not changed a 4 b 2 d 1 2 d 1 4 8 Two loops of wire are arranged so that a changing current in one the primary will induce a current in the other the secondary The secondary loop has twice as many turns as the primary loop As long as the current in the primary is steady at 3 A the current in the secondary will be a 6 A b 3 A c 1 5 A d zero 9 A 0 200 m wire is moved parallel to a 0 500 T magnetic field at a speed of 1 50 m s What emf is induced across the ends of the wire a 2 25 V b zero c 0 60 V d 1 00 V 10 The primary coil in an ideal transformer has N turns To output half the input potential difference the secondary coil should have a N 2 turns b N turns c N2 turns 11 Find the frequency of x rays of wavelength 10 a 3 1018 Hz b 3 108 Hz 10 d 2N turns m c 3 1016 Hz d 6 109 Hz 12 Consider an AC circuit containing a single capacitor C If the frequency is increased by a factor of 8 how does the amplitude of the current change a The current increases by a factor of 8 c The current decreases by a factor of 16 b The current increases by a factor of 64 d The current decreases by a factor of 8 Name Student ID Problems You MUST show ALL your work and use correct units for numerical answers to receive full credit 13 1 a A charge of 8 3 C enters at a speed of 7 4 x 106 m s into a region of space with magnetic field The angle between the velocity of the charge and the magnetic field is 52o If the charge feels a force of 5 4 x 10 3 N acting on it what is the magnitude of the magnetic field it experiences 5 points 13 2 A current of 3 0 A is carried by a wire A particle of charge 6 5 mC is placed next to the wire at a distance of 0 05 m and it moves with an initial speed of 280 m s as shown in the figure b Calculate the magnitude and direction of magnetic field generated by the wire at the location of the charge 4 2 points c Calculate the magnitude and direction of the force exerted on the charged particle immediately after it is placed at 0 05 m 4 2 points d If instead of a positive charge this problem is done for a negatively charged particle what will be the direction of the magnetic force it experiences 3 points Clearly circle the answer of your choice 1 towards the wire 2 away from the wire 3 parallel to the wire 4 anti parallel to the wire v I 6 5 C Name Student ID 14 A circular coil of radius 5 cm is made of 200 turns of copper wire The wire making up the coil has a resistance of 5 and the ends of the wire are connected to form a closed circuit a Initially a uniform magnetic field of 1 1 T points perpendicular through the plane of the coil as shown in the figure Calculate the magnetic flux through the coil 4 points b If the magnitude of the magnetic field is kept constant but the direction is changed by 180o in 0 1 s calculate the emf induced in the coil 6 points c What is the current that flows through the coil during that time 3 points d If a square coil again with 200 turns of side 10 cm is used calculate the magnetic flux through the coil 4 points e If the plane of the coil originally perpendicular to the magnetic field is turned by 90o what will happen to the magnetic flux 3 points Clearly circle the answer of your choice 1 remain the same 2 zero 3 negative or 4 maximum Name Student ID 15 Consider an RLC circuit R 100 L 0 5 H and C 10 F The frequency of the AC source f 60 Hz the maximum voltage Vmax 170 V a Calculate the impedance Z of the RLC circuit 6 points b Calculate the phase angle 3 points the RLC the circuit c Calculate the rms current in the circuit and the average power consumed by the circuit 3 4 points d What is the maximum voltage across the inductor 4 points e If the frequency of the AC source is tuned …