Consider the following statements for steam turbines:

1. The ratio of actual enthalpy drop to isentropic enthalpy drop is known as mechanical efficiency.

2. The ratio of enthalpy drop in moving blades to enthalpy drop in the stage is known as degree of reaction.

3. Rateau turbine is the example of reaction turbine.

4. Curtis turbine is the example of impulse turbine.

Which of the above statements are correct?