Slide 1 / 50 Slide 2 / 50 1 A beam of electrons travels between two parallel coils of wire, as shown in the figures above. When the coils do not carry a current, the electron beam is undeflected and hits the center of the screen, as indicated by the dashed line. When the coils carry a constant current I, the electron beam is deflected toward which edge of the screen? AP Physics 2 A The top B The bottom Electromagnetic Induction C The left Multiple Choice D None, it is not deflected www.njctl.org Slide 3 / 50 Slide 4 / 50 2 A long straight wire carries a current I toward the right. What is the 3 The two circular wire loops are represented above lie on the same direction of the magnetic field resulting from the wire at point x? axis. If the current I in loop X is increasing linearly with respect to time, which of the following is true of the induced current in loop Y ? A Out of the page B Into the page A It is in the same direction as that in loop X and is increasing C Toward the left with respect to time D Toward the right B It is in the opposite direction of that in loop X and is increasing with respect to time C It is in the same direction as that in loop X and is constant D It is in the opposite direction of that in loop X and constant Slide 5 / 50 Slide 6 / 50 4 An electron enters the magnetic field above. What direction is the 5 Which of the following diagrams accurately portrays the magnetic magnetic force acting on the charge when it enters? field resulting from a wire directed out of the page? B A Up A B Down C Right D Left D C
Slide 7 / 50 Slide 8 / 50 6 A conducting loop of wire with radius r is placed in an increasing 7 A loop of conducting wire with length L and width W is entering a magnetic field B directed into the page as shown above. What the magnetic field B at velocity c. What direction will the induced direction of the induced current of the wire? current travel in? A Clockwise A Clockwise B Counterclockwise B Counterclockwise C Up C Up D Down D Down Slide 9 / 50 Slide 10 / 50 8 A loop of conducting wire with length L and width W is entering a 9 A loop of conducting wire with length L and width W is entering a magnetic field B at velocity v. What is the induced EMF? magnetic field B at velocity v. The loop of wire has a resistance R. What is the value of the induced current? A IBL A BLv/R B BLv B ILB/R C BL/v C BL/vR D There is no induced EMF D There is no induced current Slide 11 / 50 Slide 12 / 50 10 A loop of conducting wire with length L and width W is entering a 11 A loop of conducting wire with length L and width W is entering a magnetic field B at velocity v. What is the direction of the magnetic magnetic field B at velocity v. What is the direction of the magnetic force on the loop as it enters magnetic field B? force on the loop as it leaves magnetic field B? A Up A Up B Down B Down C Right C Right D Left D Left
Slide 13 / 50 Slide 14 / 50 12 A magnet is slowly descending into a loop of wire. What direction is 13 A conducting circular loop of wire with radius r and resistance R is the induced current in? placed in a changing magnetic field B directed upwards at an angle θ. What is the magnetic flux through the loop? A 2πrB cosθ A Clockwise B 2πrB sinθ B Counterclockwise C Bπr 2 cosθ C Upwards D Bπr 2 sinθ D Downwards Slide 15 / 50 Slide 16 / 50 14 Two wires with current I are a distance r apart. . In what direction is 15 What is the magnitude of the force between the wires? the force on the left wire? A μ o I 2 /2r A Up B μ o I/2r B Down C μ o I 2 /r 2 C Right D 0 D Left Slide 17 / 50 Slide 18 / 50 16 A square coil of wire with a side length of 10 cm is looped around 17 A square coil of wire with a side length of 10 cm is looped around 10 times. The coil sits in an increasing magnetic field. The 10 times. The coil sits in an increasing magnetic field. The magnetic field increases linearly from 1T to 2T within 5 seconds. magnetic field increases linearly from 1T to 2T within 5 seconds. If What is the induced EMF of the coil? the same loop of wire has a resistance of 2Ω, what is the induced current in the loop? A 200 V A 100 A B 20 V B 20 A C 2 V C 1 A D 0.02 V D 0.01 A
Slide 19 / 50 Slide 20 / 50 18 In the diagram above, a conducting rod with length L moves 19 In the diagram above, a conducting rod with length L moves horizontally on a set of conducting rails at a constant velocity v horizontally on a set of conducting rails at a constant velocity v through a magnetic field B. What direction is the induced current in through a magnetic field B. What is the induced EMF in the circuit? the circuit? A Into the page A Clockwise B Out of the page B Counterclockwise C Left C Right D Right D Left Slide 21 / 50 Slide 22 / 50 20 In the diagram above, a conducting rod with length L moves 21 In the diagram above, a conducting rod with length L moves horizontally on a set of conducting rails at a constant velocity v horizontally on a set of conducting rails at a constant velocity v through a magnetic field B. What is the induced EMF in the through a magnetic field B. If the resistance of the rod is R, what is circuit? the magnitude of the induced current in the circuit? A Bv A Bv/R B vR B v C BLv C BLv/R D 0 D 0 Slide 23 / 50 Slide 24 / 50 22 In the diagram above, a conducting rod with length L moves 23 In the diagram above, a conducting rod with length L moves horizontally on a set of conducting rails at a constant velocity v horizontally on a set of conducting rails at a constant velocity v through a magnetic field B. If the resistance of the rod is R, what is through a magnetic field B.What direction is the magnetic force in? the magnitude of the magnetic force acting on the rod? A Left A B 2 vL/R B Right B vLB/R C Up C B 2 L 2 v/R D Down D 0
Slide 25 / 50 Slide 26 / 50 24 In the diagram above, a conducting rod with length L moves 25 In the diagram above, a conducting rod with length L moves horizontally on a set of conducting rails at a constant velocity v horizontally on a set of conducting rails at a constant velocity v through a magnetic field B. Given the direction of the magnetic through a magnetic field B. There is a friction between the rod and force, which of the following statements must be true? the track it is riding on. The coefficient of friction is μ. If the rod has mass m, what is the applied force? A B 2 L 2 v/R + μmg B B 2 L 2 v/R - μmg C B 2 Lv/R + μmg A The track has a resistance of 2R D B 2 Lv/R - μmg B The induced magnetic field is into the page C There is a force pushing the rod to the left D There is a force pushing the rod to the right Slide 27 / 50 Slide 28 / 50 26 What is the SI unit for EMF? 27 When a current runs through a wire, a magnetic field is created. However, computer cables create little to no magnetic field external to their insulation. How is this possible? (Hint: computer cables A Farad contain multiple wires inside) B Ohm A The cables are insulated with plastic C EMF B The supply and return cables run anti parallel and their magnetic fields essentially cancel out D Volt C The supply and return cables run parallel and their magnetic fields essentially cancel out D The currents are too small to create a significant magnetic field Slide 29 / 50 Slide 30 / 50 28 A circular loop of conducting wire is placed in a magnetic field B 29 A current flows to the right through wire A, which is fixed in place. and has radius r. The loop is spinning in the magnetic field at an Wire B are held in equilibrium by the magnetic force and the angular velocity of ω with respect to its diameter. Which of the gravitational force. What is the direction of the current through wire following equations can be used to find the magnetic flux as a B? function of time? A Bπr 2 cos(t) A Right B Bπr 2 sin(t) B Left C Bπr 2 sin(ωt) C Both directions D Bπr 2 cos(ωt) D There is no current in wire B; the magnetic field from wire A attracts the metal in wire B
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