Closeness of packing is maximum in case of __________ crystal lattice.

Out of the following, the lowest packing of atoms exists in __________ crystal lattice structure.

A

Hexagonal close, packed (hcp)

B

Face centred cubic (fcc)

C

Body centred cubic (bcc)

D

Simple cubic

In case of saddle packing (e.g., berl and intralox saddles), the maximum size of the packing should not exceed __________ of the column diameter.

A

$${\frac{1}{5}^{{\text{th}}}}$$

B

$${\frac{1}{{15}}^{{\text{th}}}}$$

C

$${\frac{1}{{30}}^{{\text{th}}}}$$

D

$${\frac{1}{{50}}^{{\text{th}}}}$$

In an absorption coloumn, the flooding velocity for random packing is __________ that for stacked/regular packing.

A

Greater than

B

Smaller than

C

Equal to

D

Either A, or B ; depends on the type of packing

Stacked packing compared to dumped packing

A

Provides poorer contact between the fluids

B

Gives lower pressure drop

C

Both A & B

D

Gives higher pressure drop

Deformation band is absent in materials having __________ lattice crystal structure.

A

Fcc

B

Bcc

C

Hcp

D

None of these

Quartz crystal is most commonly used in crystal oscillators because ___________

A

It has superior electrical properties

B

It is easily available

C

It is quite inexpensive

D

None of the above

The crystal oscillator frequency is very stable due to ___________ of the crystal

A

Rigidity

B

Vibrations

C

Low Q

D

High Q

If the crystal frequency changes with temperature, we say that crystal has ___________ temperature coefficient

A

Positive

B

Zero

C

Negative

D

None of the above

Which of the following packing materials provides for maximum mass transfer?

A

Lessig rings

B

Raschig rings

C

Cross-partition rings

D

All of the above

Most important factor to be considered in the selection of packings for absorbers is the __________ of packing.

A

Size

B

Durability

C

Porosity

D

Cost

Closeness of packing is maximum in case of __________ crystal lattice.

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