In Newton's law of viscosity, which states that the shear stress is proportional to the __________ co-efficient of viscosity is called dynamic or absolute viscosity (where, V = velocity, $${{\text{V}}_{\text{g}}}$$ = velocity gradient).

In Newton's law of viscosity, which states that the shear stress is proportional to the __________ Co-efficient of viscosity is called dynamic or absolute viscosity(where, V = velocity, Vg = velocity gradient ).

A

V²

B

1/V²

C

1/Vg

D

Vg

Tresca or maximum-shear stress criteria assumes that yielding occurs when the maximum shear stress reaches a value of the shear stress in the uniaxial tension test. Assume the principal stress being σ1, σ2, σ3 where σ1 is largest, and σ3 is the smallest principal stresses. Find the value of minimum shear stress to cause yielding, given that yield stress in tension is equal to σo?

A

τ = σo

B

τ = σo/2

C

τ = σo/3

D

τ = σo/4

Fluid which does not follow the newtons law that is shear stress is not proportional to rate of shear strain known as

A

newtons law of viscosity

B

non-newtonian fluids

C

$$\tau = \mu $$

D

$$\tau = \frac{{du}}{{dy}}$$

The Rheological behaviour of concrete, when represented by shear stress vs rate of shear, is characterized as Where : τ shear stress, Τ0 = (initial) yield value, μ = at-point plastic viscosity, γ̇ = at point rate of shear.

A

τ = τ₀ + μ . γ̇

B

τ₀ = τ + μ . γ̇

C

$\frac{\tau }{{{\tau _0}}} = \mu .\dot \gamma$

D

τ = μ . γ̇

Which of the following factors are affecting critical shear stresses? 1. Purity of metals reduces the critical shear stress 2. Surface films greatly enhance the critical shear stress 3. Rise in temperature 4. Rate of deformation and the extent of initial deformation also help in raising the critical shear stress

A

1, 2 and 3 only

B

1, 2 and 4 only

C

1, 3 and 4 only

D

1 ,2, 3 and 4

Consider the following statements: 1. If x is directly proportional to z and y is directly proportional to z, then (x2 - y2) is directly proportional to z2. 2. If x is inversely proportional to z and y is inversely proportional to z, then (xy) is inversely proportional to z2. Which of the above statements is/are correct?

A

1 only

B

2 only

C

Both 1 and 2

D

Neither 1 nor 2

For absolute chamber gas temperature Tg, absolute liquid temperature Tl, absolute wall temperature on the gas side of the wall Twg, overall film coefficient h, gas film coefficient hg and liquid film coefficient hl, determine the expression for heat transferred per unit area q.

A

q = hl (To – Twg)

B

q = h (To – Twg)

C

q = hg (To – Twg)

D

q = hg/h (Twg – To)

Newton law of viscosity states that shear stress is proportional to rate of shear at any point in the fluid.

A

True

B

False

Shear stress versus shear rate behavior of four different types of fluids (I, II, III and IV) are shown in the figure below.
Basic Principles of Biotechnology mcq question image

Basic Principles of Biotechnology mcq question image

Which one of the following options is correct?

A

I-Newtonian, II-Bingham plastic, III-Dilatant, IV-Pseudoplastic

B

I-Pseudoplastic, II-Dilatant, III-Newtonian, IV-Bingham plastic

C

I-Newtonian, II-Pseudoplastic, III-Bingham plastic, IV-Dilatant

D

I-Newtonian, II-Bingham plastic, III-Pseudoplastic, IV-Dilatant

A fluid, in which shear stress is more than the yield value and shear stress is proportional to the rate of shear strain is known as:

A

Newtonian fluid

B

Ideal Plastic Fluid

C

Real Fluid

D

Ideal fluid

In Newton's law of viscosity, which states that the shear stress is proportional to the __________ co-efficient of viscosity is called dynamic or absolute viscosity (where, V = velocity, $${{\text{V}}_{\text{g}}}$$ = velocity gradient).

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