In a reaction turbine, when steam flows through the fixed blades,

In a reaction turbine, the flow of steam goes through both fixed and moving blades. Here's what happens to the steam as it flows through the fixed blades:

The fixed blades, also known as nozzles or guide vanes, serve to direct the flow of steam onto the moving blades at a specific angle. They do not impart any significant kinetic energy to the steam.

As the steam flows through the fixed blades, its pressure decreases. This is because the fixed blades are designed to convert the pressure energy of the steam into kinetic energy by accelerating the steam.

Simultaneously, the velocity of the steam increases as it passes through the fixed blades. This is a result of the pressure drop, which causes the steam to accelerate to maintain conservation of mass.

So, in a reaction turbine, when steam flows through the fixed blades, Option B: Pressure decreases while velocity increases is the correct description of what happens.