If a tree fall in a forest does it make a sound?

According to the tide table below what time of day will the highest tide occur?

A10nc charge sits at a point in space where the magnitude of the electric field is 1500 n/c. what will the magnitude of the field be if the 10 nc charge is replaced by a 20 nc charge? assume the system is big enough to consider the charges as small test charges.

If frequency goes down, what happens to wavelength? does it get shorter or longer?