1 1. The current / in the long straight wire is moving right as shown and increasing in magnitude. What direction is the induced current in the loop of wire? (Solve problems with Lenz's law.) 12. A transformer has an input voltage of 100 V and an output voltage of 10,000 volts. If the primary coil has 100 turns and the input current is 2 A, what is the output current, and how many turns does the secondary coil have? (Understand and use the transformer equations). 13. Explain how the capacitive reactance changes with ac frequency? What about the inductive reactance? (Know how capacitors and inductors change their resistance with frequency and use that in Ohm's law if necessary). 14. When a magnetic field is changed from 0 T to 1.5 T, an emf of 2.5 V is created in a loop of wire with a radius of 50 cm. How fast was the magnetic field changed? (Be able to solve general equations with Faraday's law and use the induced emf in Ohm's law.) 15. A rod of length L = 10 cm slides to the right at a constant speed v = 5.0 m/s along frictionless conducting rails attached to a resistor in a uniform magnetic field B = 0.80 T pointing out of R the page as shown by the dots in the figure. If the current in the resistor is 0.2 A, what is its resistance? (Be able to solve Faraday's law problems with motional emf and use that emf in Ohm's law). 16. When the energy stored in a solenoid is doubled, how has the magnetic field changed? (Know how to use the equation for magnetic energy stored in a magnetic field.) 17. If the frequency of a generator is doubled, what happens to the maximum voltage? (Understand and know how to use the equation for a generator.)