Thermal Expansion

IMPORTANT

Thermal Expansion: Overview

This Topic covers sub-topics such as Thermal Expansion, Anomalous Expansion of Water, Coefficients of Thermal Expansion, Thermal Stresses, Thermal Expansion in Solids, Linear Expansion in Solids and, Relation between Coefficients of Thermal Expansion

Important Questions on Thermal Expansion

HARD
IMPORTANT

A metal rod is fixed rigidly at two ends so as to prevent its thermal expansion. If L, α and Y respectively denote the length of the rod, coefficient of linear thermal expansion and Young’s modulus of its material, then for an increase in temperature of the rod by T, the longitudinal stress developed in the rod is

EASY
IMPORTANT

What is the coefficient of volume expansion of an ideal gas?

EASY
IMPORTANT

Most matter contracts on heating and expands on cooling (Yes\No).

MEDIUM
IMPORTANT

Co-efficient of linear expansion for ionic solid is αi and for non-ionic solid be αn then

EASY
IMPORTANT

Length of a wire at room temperature is 4.55 m. When the temperature increases upto 100 , then its length becomes 4.57 m. The coefficient of linear expansion (α) of the given wire is

HARD
IMPORTANT

A steel wire of uniform cross-section of 1 mm2 is heated upto 50°C and clamped rigidly at its ends. If the temperature of wire falls to 40°C, change in tension in the wire is (coefficient of linear expansion of steel is 1.1×10-5 C-1o and Young's modulus of elasticity of steel is 2×1011 N m-2)

EASY
IMPORTANT

A metal rod of Young's modulus Y and coefficient of thermal expansion α is held at its two ends such that its length remains invariant. If its temperature is raised by t°C, the linear stress developed in it is

MEDIUM
IMPORTANT

A metal rod of length L and cross-sectional area A is heated through T  °C. What is the force required to prevent the expansion of the rod lengthwise?

EASY
IMPORTANT

If there is an increase in the _____ of a solid body due to heating, then the expansion is called cubical expansion.

EASY
IMPORTANT

When the temperature of water decreases from _____ °C to 0 °C instead of contracting it expands, and becomes less dense.

EASY
IMPORTANT

A metal rod of Young's modulus Y and coefficient of thermal expansion α is held at its two ends such that its length remains invariant. If its temperature is raised by t°C, the linear stress developed in it, is

HARD
IMPORTANT

A metal rod of cross-sectional area 10-4 m2 is hanging in a chamber kept at 20°C with a weight attached to its free end. The coefficient of thermal expansion of the rod is 2.5×10-6 K-1 and its Young's modulus is 4×1012 N m-2. When the temperature of the chamber is lowered to T, then a weight of 5000 N needs to be attached to the rod, so that its length is unchanged. Then, T is

HARD
IMPORTANT

Draw a graph showing the variation of coefficient of volume expansion αv of copper with temperature T. What can you say about the variation of αv at higher temperatures using this graph? 

HARD
IMPORTANT

The coefficient of volume expansion αvfor metals like copper: 

HARD
IMPORTANT

A copper wire is held at the two ends by rigid supports. At 30°C, the wire is just taut, with negligible tension. Find the speed of transverse waves(in m s-1 and in closest integer) in this wire at 10°C. Given: Young modulus of copper, Y=1.3×1011 N m-2. Coefficient of linear expansion of copper,α=1.7×10-5 °C-1. Density of copper,ρ=9×103 kg m-3.

EASY
IMPORTANT

Ethyl alcohol expands less than mercury for the same rise in temperature.

EASY
IMPORTANT

The amount of thermal expansion in solids does not depend on their sizes.

EASY
IMPORTANT

In which of the following devices the bending of bimetallic strip due to thermal expansion is not used?

HARD
IMPORTANT

A steel rod with a length of 0.350 m and an aluminium rod with length of 0.250 m, both with same diameter, are placed end to end between rigid supports with no initial stress in the rods. The temperature of the rods is now raised by 60oC. The length of combined rods remains the same, but the length of individual rods change. Stress developed in each rod is β×107 N m-2. Write the value of β, where   is the greatest integer function.
Given: αs=1.2×105 oC-1, αAl=2.4×105 o-C-1, Ys=2×1011 N m-2 & YAl=0.7×1011N m-2

MEDIUM
IMPORTANT

The volume of a metal sphere increases by 0.24 % when its temperature is raised by 40 °C . The coefficient of linear expansion of the metal is