Air at a density of 1.2 kg/m<sup>3</sup> flows in a straight duct such that the velocity at the centre is 12.5 m/s. the method factor for the velocity profile is known to be 0.80. The air flow encounters a symmetric expansion such that the cross- sectional are of the duct becomes double. The static pressure value at the inlet and outlet of the expansion are 60 Pa and 90 Pa respectively. Neglecting friction the shock pressure loss on account of expansion in Pa is

Correct Answer: 15