I only need help with these three questions!

Agalvanometer has an internal resistance of 100 ω and deflects full-scale at 2.00 ma. what size resistor should be added to the galvanometer to convert it to a milliammeter capable of reading up to 4.00 ma, and how should this resistor be connected to the galvanometer?

A500g object falls off a cliff and losers 100 j from its gravitational potential energy store. if the gravitational field strength g=9.8n/kg, how high is the cliff?

Distinguish between a transverse wave and a longitudinal wave.