What causes a regular reflection?

a. light waves strike a rough, uneven surface at a 45 degree angle and are reflected back at a 90 degree angle.

b. parallel light waves strike a smooth, polished surface and reflect back in the same direction.

c. parallel light waves strike a rough, uneven surface and reflect in different directions.

d. light waves strike a smooth, polished surface at a 90 degree angle and are reflected back at a 45 degree angle.

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