Explanation:
Impulse Turbine:

There is no drop of pressure in the moving blade after coming out of the nozzle and is equal to atmospheric pressure generally.

The absolute velocity of the steam decreases as it proceeds further in the moving blade.
Reaction Turbine:
It can be observed from the following diagram.
Note: V_{1} and V_{2} are absolute velocities and V_{r1} and V_{r2} are the relative velocities component here.
Additional Information
Compounding is done to decrease the high rotational speed of simple impulse turbines to bring it down to the practical limit required for electricity generation. There are two ways of compounding i.e. pressure compounding and velocity compounding.
 In pressure compounded impulse turbine (or Rateau turbine), the total pressure drop is planned for more than one stage and each stage consists of a set of nozzles and moving blades, as the enthalpy in each stage is decreased, it decreases the rotational speed.
 In velocity compounded impulse turbine (or Curtis turbine), the total velocity drop is arranged in more than one stage and each stage consists of a set of fixed and moving blades. There is a single nozzle in which total pressure drop takes place and the high velocity obtained is converted into work in more than one stage.
The pressure and velocity variation of pressure compounded and a velocity compounded impulse turbine can be seen from the following diagram.