A packed bed has a diameter of 0.5 m and a height of 2 m. The bed is filled with spherical particles of diameter 0.01 m and has a porosity of 0.4. If the superficial velocity of a fluid passing through the bed is 0.5 m/s and the fluid density is 1000 kg/m, what is the pressure drop across the bed? Assume the fluid viscosity to be 0.01 Pa.s and the Reynolds number to be 10.