what is the difference between impulse & reaction turbine. what type of turbines are in use these days?

Answer 1

In an impulse turbine, the water (or steam) hits the blades and continues almost straight through as in a jet engine. In a reaction turbine, the water hits a semicircular cup and is completely reversed in path, normally dropping down the center with little or no momentum left. These are rarely used with gases because of having to get the output out of the way, but they work especially well with water at lower pressure as when the dam supplying the water is not very high.
Both kinds are used in various situations.