Could someone please help with #5 and #6

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.

What component of earth’s atmosphere exists entirely as a result of photosynthesis?

Which composition of water moves to begin a deepwater current?