An elephant can hear sound with a frequency of 15 hz. what is the wavelength of this wave if the speed of sound in air is 343 m/s?

Ineed extreme for task 2. my student number is 571721. many to whoever solves this correctly, im in debt to you.

Diamond will scratch quartz. true or false

Light traveling in water, nwater = 1.33, strikes a plastic block at an angle of incidence of 51.4°; part of the beam is reflected and part is refracted. if the index of refraction of the plastic is 2.0, what is the angle made by the reflected and refracted beams?