Q1] select the correct answers( 20 Marks) 1- The porosity of a bed a-is the ratio of the total volume of the bed to the volume of a voids in the bed b- is the ratio of the total volume of voids in the bed to the total volume of the bed c-is equal to the volume of voids. 2- a rotary drum filter 2 m diameter and 2m long, the area of filtration is:- a-6.28m² b-12.56m² c- neither a nor b 3-a plate and frame filter press, with 20 frames and 0.3m square and 50mm thickness, the area of filtration is: a-12 m² b-3.6m² c- neither a nor b 4-after fluidization phenomena, when the gas velocity is increased the value of pressure drop is to be: a- remain constant b- increase linearly c-neither a nor b 5-the gas velocity under aggregative or bubbling fluidization is: a-lower than minimum fluidization velocity b-greater than minimum fluidization velocity c- equal to minimum fluidization velocity 6- the air flow pattern in spray dryers is a-parallel to feed solution b-counter current to feed solution c-both a and b 7-the relation between the rate of drying and air humidity is a-proportional b-exponential c-inversely 8- the relation between the rate of drying and air temperature is a- inversely 9-free moisture content b-exponential c-proportional a-is the moisture contented by a substance in excess of the equilibrium moisture b-may include bound and unbound moisture c-all of the above answers 10- a wet solid is to be dried from 80 to 10% moisture, wet basis. The moisture to be evaporated per 1000kg of dried product is: a-630 kg b-700kg c-3500kg