Magnetic Induction Problems 1. (Do as a class) Consider the problem of a metal 1. The charge carriers in the Positive end bar sliding on metal wires in a magnetic field as wire are pushed upward of wire shown. Show that the induced voltage derived as by the magnetic force. a motional EMF is identical to the induced voltage X as derived from Faraday's law. X Conducting rail. Fixed Negative end to table and doesn't move. of wire 2. The charge carriers flow around the conducting loop as an induced current. 2. Two students are considering the induced current through the loop circuit made of two metal bars sliding on metal wires as shown in the figure to the right. X Student 1: Well, there should definitely be an induced current X X X because a motional EMF will be induced on both bars due to moving in a magnetic field. Student 2: But if I think about this like a Faraday problem, it looks like the total magnetic flux doesn't change, so there shouldn't be an induced EMF. Which student do you agree with, why and why not? How do you resolve the two points of view? 3. A circular loop of wire which is 3 cm in diameter and has 2 0 of resistance flips all the way around (like a coin) 5 times per second in a 100 G magnetic field. a. At what angles is the magnetic flux a maximum? Explain. b. At what angles is the magnetic flux zero? Explain. C. At what angles is the magnetic flux changing most rapidly? Explain. d. Determine an expression for the time dependence of the induced current in the wire loop, I (t).5. In the figures below, the magnetic field direction is indicated in blue and the metal bar(s) are moving with a velocity indicated in green. For each of the configurations, determine if the induced current is clockwise, counterclockwise, or zero. 6. A square wire loop has 100 loops of wire and an edge length of 10 cm. The wire loop is placed flat B (T) on the page in a uniform magnetic field directed out-of-the-page, which we will call positive. The graph to the right shows the strength of the 234 36 (5) magnetic field as a function of time. a. Draw in the graph for the magnetic flux as a function of time, where positive flux is De (Wbit the same direction as positive magnetic 02 01 field. 0 1 2 3 4 5 6 *t (5) -.01 b. Draw in the graph for the induced voltage -.02 where counterclockwise voltage is positive, in accordance with the right- EMA hand-rule and how we defined positive magnetic field. (Remember the minus sign 1 2 3 4 5 6 -t (5) in Faraday's law.) -1 7. A wire loop passes over the north pole of a magnet at a constant velocity, from one side across to the other side. Which of the plots best represents the induced current as a function of time as the loop passes over the magnet