Q. A steel bar 600mm long and having 30mm diameter, is turned down to 25mm diameter for one fourth of its length. It is heated at 30 C above room temperature, clamped at both ends and then allowed to cool to room temperature. If the distance between the clamps is unchanged, the maximum stress in the bar ( α = 12.5 x 10⁻⁶ per C and E = 200 GN/m²) is

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Q. A cube having each side of length p, is constrained in all directions and is heated unigormly so that the temperature is raised to T.C. What will be the stress developed in the cube?

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Q. A steel rod 10mm in diameter and 1m long is heated from 20 to 100 degree celcius, E = 200 GPa and coefficient of thermal expansion is 12 x10⁻⁶ per degree celcius. Calculate the thermal stress developed?

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Q. A cube with a side length of 1m is heated uniformly a degree celcius above the room temperature and all the sides are free to expand. What will be the increase in the volume of the cube? Consider the coefficient of thermal expansion as unity.

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Q. The thermal stress is a function of _____________

P. Coefficient of linear expansion
Q. Modulus of elasticity
R. Temperature rise

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Q. 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:

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

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Q. 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 ____________

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Q. 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 ___________

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

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Q. 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 ___________

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

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Q. Which test is conducted to measure the endurance limit of the material?

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Q. What is the process in which the metal is cooled rapidly in water after heating the metal above the lower critical temperature to increase the hardness of the material?

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Q. What is the process of heating the metal in the furnance to a temperature slightly above the upper critical temperature and cooling slowly In the furnance.

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Q. Photo stress method is ___________

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Q. What is the factor of safety?

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

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Q. Identify which factor may cause a lowered body temperature:

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Q. If a bar of two different length are in a line and P load is acting axially on them then what will be the change in length of the bar if the radius of both different lengths is same?

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