Related Mcqs:

1. A solid is being dried in the linear drying rate regime from moisture content Xo to XF. The drying rate is zero at X = 0 and the critical moisture content is the same as the initial moisture Xo. The drying time for M = (Ls/ARc) is (where, L = total mass of dry solid, A = total surface area for drying Rc = Constant maximum drying rate per unit area X = moisture content (in mass of water/mass of dry solids)) ?

   A. M(Xo – XF)
   B. M(Xo/XF)
   C. M ln(Xo/XF)
   D. MXo ln(Xo/XF)

2. A solid is being dried in the linear drying rate regime from moisture content Xo to XF. The drying rate is zero at X = 0 and the critical moisture content is the same as the initial moisture Xo. The drying time for M = (Ls/ARc) is (where, L = total mass of dry solid, A = total surface area for drying Rc = Constant maximum drying rate per unit area X = moisture content (in mass of water/mass of dry solids))_____________?

   A. M(Xo – XF)
   B. M(Xo/XF)
   C. M ln(Xo/XF)
   D. MXo ln(Xo/XF)

3. In the constant rate period of the rate of drying curve for batch drying,_________________?

   A. Cracks develop on the surface of the solid
   B. Rate of drying decreases abruptly
   C. Surface evaporation of unbound moisture occurs
   D. None of these

4. A 25 cm × 25 cm × 1 cm flat sheet weighing 1.2 kg initially was dried from both sides under constant drying rate conditions. It took 1500 seconds for the weight of the sheet to reduce to 1.05 kg. Another 1m × 1m × 1cm flat sheet of the same material is to be dried from one side only. Under the same constant drying rate conditions, the time required for drying (in seconds) from its initial weight of 19.2 kg to 17.6 kg is ____________________?

   A. 1000
   B. 1500
   C. 2000
   D. 2500

5. The drying time between fixed moisture content within diffusion controlled ‘falling rate period’ is proportional to (assuming that drying occurs from all surfaces of the solid) (where, T = thickness of the solid) ?

   A. √T
   B. T
   C. T2
   D. T3

6. The drying time between fixed moisture content within diffusion controlled ‘falling rate period’ is proportional to (assuming that drying occurs from all surfaces of the solid) (where, T = thickness of the solid) ?

   A. √T
   B. T
   C. T2
   D. T3

7. Drying of a wet solid under constant drying conditions means the exposure of the wet solid to the air of constant____________________?

   A. Humidity
   B. Velocity
   C. Temperature
   D. All A., B. & C.

8. During constant rate drying period, vaporisation rate per unit drying surface area _____________________?

   A. Decreases with time
   B. Increases with time
   C. Does not change with time
   D. Does not affect the moisture content of the wet solid

9. A solid material shows case hardening properties while drying. Which of the following should be controlled to control the drying process ?

   A. Flow rate of inlet air
   B. Relative humidity of outlet air
   C. Humidity of inlet air
   D. Temperature of the solid

10. Occurrence of ‘case hardening’ during drying of a high moisture solid cake _______________ the drying rate?

    A. Increases
    B. Decreases
    C. Does not affect
    D. Exponentially increases