While a magnet is moved towards the end of a solenoid, a voltage difference is induced between the two ends of the solenoid wire. The voltage difference would be larger if a. the speed of the magnet were increased.
b. the solenoid contained more loops (while having the same length).
c. the bar magnet produced a stronger magnetic field.
d. All of the above statements are true.
e. Only two of the above statements are true.

The frequency of a tuning fork can be found by the method shown. a long tube open at both ends is submerged in a beaker of water, and the vibrating tuning fork is placed near the top of the tube. the length l of the air column is adjusted by moving the tube vertically. the sound waves generated by the fork are reinforced when the length of the air column corresponds to one of the resonant frequencies of the tube. the smallest value for l for which a peak occurs in sound intensity is 7 cm. l what is the frequency of the tuning fork? the speed of sound in air is 345 m/s. answer in units of hz