O Hoop moves right Hoop area shrinks Hoop moves right O X X X X (e) I decreasing I increasing I constant (b) (d) (e) 1. (10 points) For each case above, indicate whether the induced current in the hoop is moving clockwise or counterclockwise. 2. (15 points) For each statement indicate whether the statement is true or false. If false, rewrite the statement to make it true. a) A transformer can be used with both DC and AC. b) The power of a battery is consumed as it is put to use. ") The current leads the voltage measured across a capacitor in an RLC circuit at resonance. d) For an electromagnetic wave the electric field and magnetic field are equal in magnitude. e) Adding a resistor in series with another resistor increases the amount of power dissipated in the circuit for a given applied voltage. 3. (9 points) After the switch is closed it takes a certain time for an LR circuit to reach 63% of its maximum current. To increase this time how would you change each of the following? For each circuit element, choose increase +, decrease -, or 00000 L doesn't matter x. R a) R b) L c) EMF of the battery 4. (10 points) A certain EM wave has an instantaneous peak magnetic field of 0.52 mT in the positive x-direction and is travelling in the positive y-direction. What is the direction (into or out of page) of the companion electrical field? 5. (10 points) Four charges are in the corners of a rectangle shown, one negative 4.0 m and three positive. All are the same magnitude of 45 ,C. What is the magnitude and direction of the electric field at the exact center of the rectangle? 3.0 m e6. A fluorescent light needs some 1200 volts to create an initial electrical are in the tube. A transformer in the base of the fixture takes the 120 volt AC house current and transforms it to the required voltage. Assume all rms values, and 100% efficiency of the transformer. a. (5 points) How many turns in the secondary of the transformer will be needed if the primary has 22 turns? b. (5 points) If the tube draws 50.0 mA of current from the secondary coil, what power is the fixture drawing at 120 V? 7. For the circuit shown 25 0 15 0 a) (5 points) What is the current drawn from the battery? b) (5 points) What is the power dissipated in the 70 5 E =15 V 60 2 10 0 70 2 resistor? 8. A square loop of wire 30 cm long and 10 cm wide is half inside a magnetic field of 10 T. The 50 2 loop has a total resistance of 1010 2. As a result 20 Q of the motion of the coil at a constant speed an EMF of 0.50 volts is developed. a) (5 points)At what speed must the loop be extracted from the B field to generat that EMF? XXX b) (5 points) What is the magnitude and direction of the induced current? X X X c) (5 points) What magnitude and direction force is required to keep the loop moving at that speed? X X X XXX 9. In an LCR circuit L = 1.5 mH and R = 10 2. The circuit is driven by a source with a peak voltage V. =110 V at a frequency of 60 Hertz. The capacitance C is chosen to cause the circuit to resonate at this frequency. a)(4 points) What is the value of Xc the capacitive reactance at this resonance frequency? b)(4 points) What is the rms current drawn from the voltage source by this circuit at resonance? c) (3 points) How much power is dissipated in the circuit? L V R