The conditions for the thermal stress in a body are given below. It is the function of coefficient of thermal expansion. It is the function of temperature rise. It is the function of modulus of elasticity. Which of the following is the CORRECT answer?

Consider the following statements concerning elasticity of concrete 1. Stress-strain behaviour of concrete is a straight line up to 10% of ultimate stress. 2. Strain determination is obtained from tangent modulus. 3. Modulus of elasticity, of concrete is also called as secant modulus. Which of the above statements are correct?

A

1, 2 and 3

B

1 and 3 only

C

1 and 2 only

D

2 and 3 only

The thermal stress is a function of _____________ P. Coefficient of linear expansion Q. Modulus of elasticity R. Temperature rise

A

P and Q

B

Q and R

C

Only P

D

Only R

Which of the following is the correct relation for the coefficient of thermal expansion? (L is length after temperature change, L0 is original length, α is coefficient of thermal expansion. and ΔT is changing in temperature)

A

L = α(1 +L0 ΔT)

B

L = (1 + α ΔT)

C

L = L0(1 + α ΔT)

D

None of the above

A cc slab of thickness 20 cm is constructed over a base of granular material with a modulus of reaction 10 kg/cm3. The maximum temperature differential between the top and bottom of the slab is found to be 19°C during summer day and night. The spacing between transverse joints is 8 m and the spacing between longitudinal joints is 4 m. The design wheel load is 5100 kg, radius of contact area is 15 cm, Poisson’s ratio is 0.15, modulus of elasticity is 3×105 kg/cm2, the thermal coefficient is 10 ×10-6 /°C and the coefficient of friction is 1.5. Using the above information, find the worst combination of stresses at the edge of the pavement.

A

51.59 kg/cm2

B

59.51 kg/cm2

C

59.15 kg/cm2

D

51.95 kg/cm2

When a circular bar tapering uniformly from diameter d₁, at one end to diameter d₂ at the other end, is subjected to an increase in temperature (t), then the thermal stress induced is (where $$\alpha $$ = Coefficient of linear expansion and E = Modulus of elasticity for the bar material)

A

$$\frac{{\alpha {\text{tE}}{{\text{d}}_1}}}{{{{\text{d}}_2}}}$$

B

$$\frac{{\alpha {\text{t}}{{\text{d}}_1}}}{{{\text{E}}{{\text{d}}_2}}}$$

C

$$\frac{{\alpha {\text{t}}{{\text{d}}_2}}}{{{\text{E}}{{\text{d}}_1}}}$$

D

$$\frac{{{\text{t}}{{\text{d}}_1}}}{{\alpha {\text{E}}{{\text{d}}_2}}}$$

Consider the following statements and choose the correct answer:
1. A direct proportionality exists between vapour pressure and the concentration of water vapour in the atmosphere
2. Relative humidity is an expression of the ratio of the actual vapour pressure of the atmosphere when saturated at the same temperature
3. A rise or fall in temperature with no change in vapour pressure will cause a drop or rise, respectively, in relative humidity
4. A rise or fall in vapour pressure with no change in temperature will be accompanied by a rise or fall, respectively, in relative humidity

A

1, 2, 3 and 4 are true

B

Only 3 and 4 are true

C

Only 2 and 4 are true

D

Only 1, 2 and 3 are true

The length, coefficient of thermal expansion and Youngs modulus of bar A are twice of bar B. If the temperature of both bars is increased by the same amount while preventing any expansion, then the ratio of stress developed in bar A to that in bar B will be ___________

A

2

B

4

C

8

D

16

A steel rod of length L and diameter D, fixed at both ends, is uniformly heated to a temperature rise of δT. The Youngs modulus is E and the coefficient of linear expansion is unity. The thermal stress in the rod is ____________

A

Zero

B

T

C

EδT

D

EδTL

What will be the thermal stress (in MPa) developed in a rod having a diameter of 4 cm and length of 2 m. It experiences heating from temperature 50°C to 200°C. The coefficient of thermal expansion is α = 10 × 10-6/°C and young’s modulus is 250 GPa?

A

300

B

325

C

350

D

375

What is the relation between linear expansion coefficient (α), Areal expansion coefficient (β) and volume expansion coefficient (ϒ)

A

α = β = γ

B

γ = 3 × α and β = 2 × α

C

${\rm{\gamma }} = {\rm{\;}}\frac{{\rm{\alpha }}}{3}{\rm{\;and\;\beta }} = \frac{{\rm{\alpha }}}{2}$

D

γ = 27 × α and β = 4 × α

The conditions for the thermal stress in a body are given below. It is the function of coefficient of thermal expansion. It is the function of temperature rise. It is the function of modulus of elasticity. Which of the following is the CORRECT answer?

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