Q1. A superconducting solenoid is to be designed to have an interior field of B= 29T with a maximum current of I=1000A. How various windings are required on a 1-meter solenoid length? Reply in units of m^-1.... What does it mean when it says answer in units of m^-1? How can I find that?

Q2. A violin string 30.0 cm long with linear density 0.650 g/m is placed near a loudspeaker that is fed by an audio oscillator of changeable frequency. It's found that string is set into oscillation only at the frequency 880 Hz and 1320 Hz as the frequency of an oscillator is varied over the range 500-1500 Hz. What is the tension in the string?

Q3. Experiments to study vision frequently require tracking the movements of a subject's eye. One way of doing so is to have the subject sit in a magnetic field as wearing special contact lenses that have a coil of very fine wire circling the edge. A current is induced in the coil each time the subject rotates his eye. Think about an experiment in which 20 turn, 6.0 a-mm-diameter coils of wire circles the subject's cornea while a 0.80 {rm T} magnetic field is directed. The subject begins by looking straight ahead. What emf is induced in the coil if the subject shifts his gaze by 8.0^circ in 0.20 {rm s}?