Which of the following materials does not form adherent oxide film on surface?

The local surface conductance for laminar film condensation on vertical surface is (where, t = film thickness)

A

∝ t

B

∝ $$\frac{1}{{\text{t}}}$$

C

∝ $$\sqrt {\text{t}} $$

D

Independent of 't'

Which metal oxide is an amphoteric oxide?

A

iron

B

aluminium

C

sodium

D

potassium

নিম্নের কোন oxide টিকে উভধর্মী oxide বলে?

A

CaO

B

MgO

C

ZnO

D

CuO

Which film has been awarded with best Environment film in 64th National film awards?

A

Kassav

B

Dashkriya

C

Ventilator

D

The tiger who crossed the line

Mr. Mamun bought 73 rolls of film. He can take 24 pictures with each roll of film. What is the total number of pictures he can take with 73 rolls of film ?

A

1,642

B

1,652

C

1,742

D

1,752

Raw materials used for producing __________ cement does not contain iron oxide.

A

Waterproof

B

Slag

C

White

D

Pozzolan

The film thickness for laminar film condensation on vertical surface __________ from top to bottom.

A

Cummulatively increases

B

Cummulatively decreases

C

Remains constant

D

And the surface conductance increase

The formation of oxide film on a metal due to atmospheric exposure reduces its

A

Toughness

B

Stiffness

C

Creep limit

D

All of the above

Oxide layer formed on the non-ferrous metal surface after its annealing is

A

Removed by acid pickling

B

Hammered into the surface

C

Removed with coarse emery cloth

D

Left as such to protect the surface

Specific surface area is the surface area of a unit __________ of materials.

A

Weight

B

Volume

C

Either A or B

D

Neither A nor B

Which of the following materials does not form adherent oxide film on surface?

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