ANS:B - directly as gas density.

For a specific centrifugal air blower operating at constant speed and capacity, the power requirement and pressure vary directly as the square of gas density. Here's why:

1. Power Requirement: The power required by a centrifugal blower is proportional to the product of the pressure (P) and the volumetric flow rate (Q) of the gas being moved. Since density (ρ) is related to mass flow rate (ρQ) and pressure (P), the power requirement P=k∗ρ∗Q P = k * ρ * QP=k∗ρ∗Q