Verified answer

Via Bernoulli's law you find that when the speed drop's, the pressure will increase and vice versa

rho * v^2/2 + p + (rho*g*H) = constant

rho is the density

v is the speed

p is the pressure

and H is the height

At subsonic speeds (< Mach 1) a nozzle is a convergent tube in which the intake has a larger section compared to the outtake. Via conservation of mass you can write (for incompressible flow, which can be assumed at subsonic speeds):

Mass flow rate 1 = Mass flow rate 2

rho1*v1*A1 = rho2*v2*A2

and incompressible => rho1=rho2

so v1*A1 = v2*A2

now, the speed at the end will be: v2 = v1*A1/A2 and because A1/A2 > 1, the speed will increase.

but we should consider pressre also too b'cas V=(2gH)^(1/2)

H= pressure head ,V= VElocity g= gravity

so if it is nozzle then u should compare with pressure also too as u consider working fluid is air and gas

When you restrict flow, you increase pressure don't you?