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
Related Mcqs:
- 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) - 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) - 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 - 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 - The drying time between fixed moisture contents within the ‘constant 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. T1.5
D. T3 - Advantage of continuous drying over batch drying is that the_____________________?
A. Drying cost per unit weight of dried product is less
B. Product with more uniform moisture content is produced
C. Equipment size required is smaller
D. All A , B. & C. - 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 - 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 - With increase in the mass velocity of the gas, the rate of drying during the constant rate period ______________, if the conduction and radiation through the solid are negligible ?
A. Increases
B. Decreases
C. Remain same
D. Increases linearly - During constant rate period, the rate of drying decreases with the______________________?
A. Decrease in air temperature
B. Increase in air humidity
C. Both A. and B.
D. Neither A. nor B.
