What type of turbine exhibits no change in pressure between the rotor inlet and exit?

The correct choice is impulse turbine because this type of turbine operates on the principle of converting pressure energy into kinetic energy through the use of jets. In an impulse turbine, the steam or gas expands through a nozzle, which accelerates it to a high velocity before hitting the rotor blades. The critical aspect of an impulse turbine is that the pressure remains constant across the rotor; therefore, there is no change in pressure between the rotor inlet and exit.

During operation, the blades change the direction of the high-velocity jet of working fluid, and the energy transfer occurs purely due to the kinetic energy of the fluid rather than a drop in pressure. The absence of any pressure drop in the rotor means that all the work is done by the high-speed jets impacting the blades, and this perfectly illustrates how impulse turbines function.

In contrast to impulse turbines, other types such as reaction turbines involve fluid expansion and a resultant pressure drop across the rotor; this is not the case for impulse turbines.