Related Questions

Effectiveness factor (E) of a catalyst pellet is defined as, E = (actual rate within pore of catalyst/rate if notsnowed by pore diffusion) Effectiveness factor for a first order reaction is given by (where, T = Thiele modulus)
A Tan hT/T
B Tan T/T
C Tan hT/tan T
D None of these
The Knudsen diffusivity is dependent on the
A Molecular velocity only
B Pore radius of the catalyst only
C Molecular mean free path only
D Molecular velocity and por radius of the catalyst
A ladder is resting against a vertical wall and its bottom is 2.5 m away from the wall. If it slips 0.8 m down the wall, then its bottom will move away from the wall by 1.4 m. What is the length of the ladder?
A 6.2 m
B 6.5 m
C 6.8 m
D \7.5 m
Knudsen diffusion is directly proportional to
A T
B $$\sqrt {\text{T}} $$
C $$\frac{1}{{\sqrt {\text{T}} }}$$
D T2
For the flow of gases through a capillary, with increase in temperature, the permeability __________ as per Knudsen law.
A Increases
B Decreases
C Remains same
D Either A or B; depends on the gas
The Token-Ring architecture was developed for a more efficient way to determine who should be transmitting at any one time. With Ethernet, collisions may take place, causing the transmitting computers to have to retransmit their data. The use of token guarantees that only one computer can transmit at a time. What happens as the network increases in size? Choose the best answer
A An additional token is added for every 1,000 nodes
B The speed of the Token-Ring network must be 16Mbps if the number of nodes is greater then 500
C The network becomes less efficient
D After the number of nodes exceeds 550, the Multistation Access Unit must be replaced by the more powerful Hyperstation Unified Bandwidth device
E The network becomes more efficient
The ratio of momentum diffusivity to thermal diffusivity is the __________ number.
A Prandtl
B Nusselt
C Stanton
D Grashoff
If mass diffusivity in a mixture is equal to the thermal diffusivity, then the Lewis number is
A 0
B 1
C > 1
When the addenda on pinion and wheel is such that the path of approach and path of recess are half of their maximum possible values, then the length of the path of contact is given by (where r = Pitch circle radius of pinion, R = Pitch circle radius of wheel and $$\varphi $$ = Pressure angle)
A $$\frac{{\left( {{{\text{r}}^2} + {{\text{R}}^2}} \right)\cos \varphi }}{2}$$
B $$\frac{{\left( {{{\text{r}}^2} + {{\text{R}}^2}} \right)\sin \varphi }}{2}$$
C $$\frac{{\left( {{\text{r}} + {\text{R}}} \right)\cos \varphi }}{2}$$
D $$\frac{{\left( {{\text{r}} + {\text{R}}} \right)\sin \varphi }}{2}$$
If Thiele modulus is __________ , then the pore diffusion resistance in a catalyst may be considered as negligible.
A 0
B ∞
C > 0.5

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