Atuning fork vibrating at a frequency of 512hz is held over the top of the jar filled with water and filled with a tap at the bottom. if the jar is 60cm tall and the speed of sound is 350ms-1, determine 1st and 2nd resonance.

Frequency of tuning fork f = 512 Hz 
Speed of sound V = 350ms-1 
Height of the jar = 60 cm = 0.06 m 
Velocity = wavelength x frequency => V = lambda x f => lambda = V / f = 350 / 512 
Wavelength = 350 / 512 = 0.684 
1st resonance at = lambda / 4 = 0.684 / 4 = 0.171 = 17 cm 
2nd resonance at = (3 x lambda)/ 4 = (3 x 0.684) / 4 = 0.513 = 51 cm

Neptune is the eighth planet from the sun. it was the first planet to get its existence predicted by  mathematical calculations  before it was actually seen through a telescope on sept. 23, 1846. irregularities in the orbit of  uranus  led french astronomer alexis bouvard to suggest that the gravitational pull from another celestial body might be responsible. german astronomer johann galle then relied on subsequent calculations to   spot neptune via telescope. previously, astronomer galileo galilei sketched the planet, but he mistook it for a star due to its slow motion. in accordance with all the other planets seen in the sky, this new world was given a name from greek and roman mythology — neptune, the roman god of the sea.