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Answer the following question. Give an example of disadvantages of thermal stress in practical use?

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प्रश्न

Answer the following question.

Give an example of the disadvantages of thermal stress in practical use?

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उत्तर

Disadvantage: Thermal stress can lead to fracture or deformation in substance under certain conditions.

Example: Railway tracks are made up of metals which expand upon heating. If no gap is kept between tracks, in hot weather, the expansion of metal tracks may exert thermal stress on track. This may lead to bending of tracks which would be dangerous. Hence, railway track is not a continuous piece but is made up of segments separated by gaps.

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  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 7: Thermal Properties of Matter - Exercises [पृष्ठ १४०]

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बालभारती Physics [English] Standard 11 Maharashtra State Board
पाठ 7 Thermal Properties of Matter
Exercises | Q 2. (xvi) | पृष्ठ १४०

संबंधित प्रश्‍न

A hole is drilled in a copper sheet. The diameter of the hole is 4.24 cm at 27.0 °C. What is the change in the diameter of the hole when the sheet is heated to 227 °C? Coefficient of linear expansion of copper = 1.70 × 10–5 K–1.


A brass rod of length 50 cm and diameter 3.0 mm is joined to a steel rod of the same length and diameter. What is the change in length of the combined rod at 250 °C, if the original lengths are at 40.0 °C? Is there a ‘thermal stress’ developed at the junction? The ends of the rod are free to expand (Co-efficient of linear expansion of brass = 2.0 × 10–5 K–1, steel = 1.2 × 10–5 K–1).


The coefficient of volume expansion of glycerin is 49 × 10–5 K–1. What is the fractional change in its density for a 30 °C rise in temperature?


A 10 kW drilling machine is used to drill a bore in a small aluminium block of mass 8.0 kg. How much is the rise in temperature of the block in 2.5 minutes, assuming 50% of power is used up in heating the machine itself or lost to the surroundings Specific heat of aluminium = 0.91 J g–1 K–1


If two bodies are in thermal equilibrium in one frame, will they be in thermal equilibrium in all frames?


Is it possible for two bodies to be in thermal equilibrium if they are not in contact?


A system X is neither in thermal equilibrium with Y nor with Z. The systems Y and Z


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A gas thermometer measures the temperature from the variation of pressure of a sample of gas. If the pressure measured at the melting point of lead is 2.20 times the pressure measured at the triple point of water, find the melting point of lead.


The density of water at 0°C is 0.998 g cm–3 and at 4°C is 1.000 g cm–1. Calculate the average coefficient of volume expansion of water in the temperature range of 0 to 4°C.


Answer the following question.

Derive the relation between three coefficients of thermal expansion.


Answer the following question.

State applications of thermal expansion.


Answer the following question.

What is thermal stress?


Solve the following problem.

A blacksmith fixes iron ring on the rim of the wooden wheel of a bullock cart. The diameter of the wooden rim and the iron ring are 1.5 m and 1.47 m respectively at room temperature of 27 °C. To what temperature the iron ring should be heated so that it can fit the rim of the wheel? (αiron = 1.2 × 10–5K–1).


A metal rod is heated to t°C. A metal rod has length, area of cross-section, Young's modulus and coefficient of linear expansion as 'L', 'A', 'Y' and 'a' respectively. When the rod is heated, the work performed is ______.


A hot body at a temperature 'T' is kept in a surrounding of temperature 'T0'. It takes time 't1' to cool from 'T' to 'T2', time t2 to cool from 'T2' to 'T3' and time 't3' to cool from 'T3' to 'T4'. If (T - T2) = (T2 - T3) = (T3 - T4), then ______.


A bimetallic strip is made of aluminium and steel (αAl > αsteel) . On heating, the strip will ______.


An aluminium sphere is dipped into water. Which of the following is true?


The radius of a metal sphere at room temperature T is R, and the coefficient of linear expansion of the metal is α. The sphere is heated a little by a temperature ∆T so that its new temperature is T + ∆T. The increase in the volume of the sphere is approximately ______.


The height of mercury column measured with brass scale at temperature T0 is H0. What height H' will the mercury column have at T = 0°C. Coefficient of volume expansion of mercury is γ. Coefficient of linear expansion of brass is α ______.


A metal ball immersed in water weighs w1 at 0°C and w2 at 50°C. The coefficient of cubical expansion of metal is less than that of water. Then ______.


A disc is rotating freely about its axis. The percentage change in angular velocity of a disc if temperature decreases by 20°C is ______.

(coefficient of linear expansion of material of disc is 5 × 10-4/°C)


A clock with an iron pendulum keeps the correct time at 15°C. If the room temperature is 20°C, the error in seconds per day will be near ______.

(coefficient of linear expansion of iron is 1.2 × 10-5/°C) 


A metal rod Y = 2 × 1012 dyne cm-2 of coefficient of linear expansion 1.6 × 10-5 per °C has its temperature raised by 20°C. The linear compressive stress to prevent the expansion of the rod is ______.


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The volume of a block of metal at 30°C changes by 0.12% when its temperature is increased to 70°C. The coefficient of linear expansion of the metal is ______.


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