In an open pipe 80 cm long you find the 5th harmonic to be 1062.5 Hz, what would happen to the frequency if you covered the end of the pipe?

Adouble-slit experiment is performed with light of wavelength 600 nm. the bright interference fringes are spaced 1.8 mm apart on the viewing screen. what will the fringe spacing be if the light is changed to a wavelength of 400 nm? ?

A6,600 kg train car moving at +2.0 m/s bumps into and locks together with one of mass 5,400kg moving at -3.0m/s. what is their final velocity? +0.50 m/s -1.0 m/s +2.5 m/s -0.25 m/s

Give one example to show that when substances are mixed, it may result in a chemical or a physical change depending on the conditions.