Questions and answers for exam Preparation

MCQs

Total Questions : 98 | Page 7 of 10 pages

Question 61. The thermal stress is a function of _____________
P. Coefficient of linear expansion
Q. Modulus of elasticity
R. Temperature rise

P and Q
Q and R
Only P
Only R

Discuss Question

Answer: Option D. -> Only R
Answer: (d).Only R

Question 62. Which one of the following pairs is NOT correctly matched?

Temperature strain with permitted expansion – ( αTl – δ)
Temperature thrust – ( αTE)
Temperature stress – (αTEA)
Temperature stress with permitted expansion – E(αTl – δ) / l

Discuss Question

Answer: Option A. -> Temperature strain with permitted expansion – ( αTl – δ)
Answer: (a).Temperature strain with permitted expansion – ( αTl – δ)

Question 63. A steel rod is heated from 25 to 250 degree celcius. Its coefficient of thermal expansion is 10⁻⁵ and E = 100 GN/m². if the rod is free to expand, the thermal stress developed in it is:

100 kN/m²
240 kN/m²
Zero
Infinity

Discuss Question

Answer: Option C. -> Zero
Answer: (c).Zero

Question 64. 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 ____________

Zero
T
EδT
EδTL

Discuss Question

Answer: Option C. -> EδT
Answer: (c).EδT

Question 65. Which one of the following are true for the thermal expansion coefficient?

αaluminium > αbrass> αcopper > αsteel
αbrass > αaluminium > αcopper > αsteel
αcopper > αsteel > αaluminium > αbrass
αsteel > αaluminium > αbrass > αcopper

Discuss Question

Answer: Option A. -> αaluminium > αbrass> αcopper > αsteel
Answer: (a).αaluminium > αbrass> αcopper > αsteel

Question 66. 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 ___________

Discuss Question

Answer: Option B. -> 4
Answer: (b).4

Question 67. Which test is conducted to measure the ability of a material to resist scratching, abrasion, deformation and indentation?

Creep test
Fatigue test
Hardness test
Compression test

Discuss Question

Answer: Option C. -> Hardness test
Answer: (c).Hardness test

Question 68. A uniform, slender cylindrical rod is made of a homogeneous and isotropic material. The rod rests on a frictionless surface. The rod is heated uniformly. If the radial and longitudinal thermal stress are represented by σx and σz, then ___________

σx = 0, σy = 0
σx not equal to 0, σy = 0
σx = 0, σy not equal to 0
σx not equal to 0, σy not equal to 0

Discuss Question

Answer: Option A. -> σx = 0, σy = 0
Answer: (a).σx = 0, σy = 0

Question 69. Which one of the following has the largest value of thermal coefficient?

Brass
Copper
Steel
Aluminium

Discuss Question

Answer: Option D. -> Aluminium
Answer: (d).Aluminium

Question 70. If a bar of two sections of different diameters of same length are in a line and P load is acting axially on them then what will be the change in length of the bar?