In liquids in order to measure the viscosity of fluid experimentally we consider the variation of shear stress with respect to what property?

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

Statement 1: Considering the equation, μ_a= τ/γ = Kγ(n-1) , for pseudo plastic fluids, n<1 and they’re called Shear thinning liquids and dilatant fluids are called Shear thickening liquids as n>1. Statement 2: Cooked starch solution is a Shear thinning liquid and dairy cream is a Shear thickening liquid.

A

True, False

B

True, True

C

False, False

D

False, True

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

As per Newton's law of viscosity, the shear stress for a given rate of angular deformation of fluid is proportional to(where, μ = fluid viscosity)

A

1/μ

B

μ

C

μ²

D

1/μ²

As per Newton's law of viscosity, the shear stress for a given rate of angular deformation of fluid is proportional to (where, $$\mu $$ = fluid viscosity)

A

$$\frac{1}{\mu }$$

B

$$\mu $$

C

$${\mu ^2}$$

D

$$\frac{1}{{{\mu ^2}}}$$

For turbulent flow (NRe > 2100) of low viscosity fluid (μ > 20cp) in steel pipes, the optimum inside pipe diameter is given by (where, Q = fluid flow rate, ft³/sec.ρ = fluid density, lb/ft³.μ = fluid viscosity, centipoise D_i = optimum inside pipe diameter, inches)

A

D_{i, opt} = 3.9 Q^0.45.ρ^0.13

B

D_{i, opt} = 3.9 Q^0.45.μ^0.95

C

D_{i, opt} = 4.7 Q^0.36.μ^3.2ρ^0.13

D

D_{i, opt} = 3 Q^0.36.μ^0.88

A wall bracket is attached to the wall by means of 2 identical bolts, one at A and one at B. The force of 20kN acts at a distance of 400mm. Bolt A lies at a distance of 50mm from axis of tilt and bolt B 500mm. Allowable shear stress in the bolts is 100N/mm² and tensile is 40N/mm². Find the radius of Mohr circle which can be made from the shear stress and tensile stress acting on bolts.(Consider bolt under max stress and area of bolt is A)

A

10000/A N/mm²

B

6378.5/A N/mm²

C

10755.7/A N/mm²

D

None of the listed

If nominal shear stress $${\tau _{\text{v}}}$$ exceeds the design shear strength of concrete $${\tau _{\text{c}}}$$, the nominal shear reinforcement as per IS : 456-1978 shall be provided for carrying a shear stress equal to

A

$${\tau _{\text{v}}}$$

B

$${\tau _{\text{c}}}$$

C

$${\tau _{\text{v}}} - {\tau _{\text{c}}}$$

D

$${\tau _{\text{v}}} + {\tau _{\text{c}}}$$

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

In liquids in order to measure the viscosity of fluid experimentally we consider the variation of shear stress with respect to what property?

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