1.
The apparent coefficient of expansion of a liquid when heated in a copper vessel is $$C$$ and that when heated in a silver vessel is $$S.$$ If $$A$$ is the linear coefficient of expansion of copper, then the linear coefficient of expansion of silver is
The area of circular hole increases when we heat the metal sheet & expansion of metal sheet will be independent of shape & size of the hole.
3.
A horizontal tube, open at both ends, contains a column of liquid. The length of this liquid column does not change with temperature. Let $$\gamma =$$ coefficient of volume expansion of the liquid and $$\alpha =$$ coefficient of linear expansion of the material of the tube, then
Let $${A_0}$$ and $${A_t}$$ be the areas of cross-section of the tube at temperature 0 and $$t$$ respectively,
$$l = $$ length of the liquid column (constant)
$${V_0}$$ and $${V_t}$$ be the volumes of the liquid at expansion. temperature 0 and $$t$$ respectively,
$$\eqalign{
& {V_0} = \ell {A_0} \cr
& {V_t} = \ell {A_t} \cr
& {V_t} = {V_0}\left( {1 + \gamma t} \right){A_t} = {A_0}\left( {1 + 2\alpha t} \right) \cr
& \therefore {V_t} = \ell {A_0}\left( {1 + 2\alpha t} \right) = {V_0}\left( {1 + \gamma t} \right) \cr
& = \ell {A_0}\left( {1 + \gamma t} \right)\,\,{\text{or}}\,\,\gamma = 2\alpha . \cr} $$
4.
The density of steel at $${0^ \circ }C$$ is $$8.0\,g/cc.$$ At what temperature is density lesser by $$0.1\,\% ?$$ Co-efficient of linear expansion of steel is $${10^{ - 5}}{/^ \circ }C.$$
5.
A metal ball immersed in alcohol weighs $${W_1}$$ at $${0^ \circ }C$$ and $${W_2}$$ at $${50^ \circ }C.$$ The co-efficient of expansion of cubical the metal is less than that of the alcohal. Assuming that the density of the metal is large compared to that of alcohol, it can be shown that
The volume of cavity inside the solid ball increases when it is heated.
8.
A piece of metal weighs $$45g$$ in air and $$25g$$ in a liquid of density $$1.5 \times {10^3}kg - {m^3}$$ kept at $${30^ \circ }C.$$ When the temperature of the liquid is raised to $${40^ \circ }C,$$ the metal piece weighs $$27g.$$ The density of liquid at $${40^ \circ }C,$$ is $$1.25 \times {10^3}kg - {m^3}.$$ The coefficient of linear expansion of metal is
9.
An iron tyre is to be fitted on to a wooden wheel $$1m$$ in diameter. The diameter of tyre is $$6\,mm$$ smaller than that of wheel. The tyre should be heated so that its temperature increases by a minimum of (the coefficient of cubical expansion of iron is $$3.6 \times {10^{ - 5}}{/^ \circ }C$$ )
Initial diameter of tyre $$ = \left( {1000 - 6} \right)\,mm = 994\,mm,$$ so initial radius of tyre $$R = \frac{{994}}{2} = 497\,mm$$
and change in diameter $$\Delta D = 6\,mm$$
so $$\Delta R = \frac{6}{2} = 3\,mm$$
After increasing temperature by $$\Delta \theta $$ tyre will fit onto wheel
Increment in the length (circumference) of the iron tyre
$$\eqalign{
& \Delta L = L \times \alpha \times \Delta \theta = L \times \frac{\gamma }{3} \times \Delta \theta \,\,\left[ {{\text{As}}\,\alpha = \frac{\gamma }{3}} \right] \cr
& 2\pi \Delta R = 2\pi R\left( {\frac{\gamma }{3}} \right)\Delta \theta \Rightarrow \Delta \theta \cr
& = \frac{3}{\gamma }\frac{{\Delta R}}{R} = \frac{{3 \times 3}}{{3.6 \times {{10}^{ - 5}} \times 497}} \Rightarrow \Delta \theta \simeq {500^ \circ }C \cr} $$
10.
The value of coefficient of volume expansion of glycerin is $$5 \times {10^{ - 4}}{K^{ - 1}}.$$ The fractional change in the density of glycerin for a rise of $${40^ \circ }C$$ in its temperature is
Given, the value of coefficient of volume expansion of glycerin is $$5 \times {10^{ - 4}}{K^{ - 1}}.$$
As, original density of glycerin, $$\rho = {\rho _0}\left( {1 + Y\Delta T} \right)$$
$$ \Rightarrow \rho - {\rho _0} = {\rho _0}Y\Delta T\,$$
Thus, fractional change in the density of glycerine for a rise of $${40^ \circ }C$$ in its temperature,
$$\eqalign{
& \frac{{\rho - {\rho _0}}}{{{\rho _0}}} = Y\Delta T = 5 \times {10^{ - 4}} \times 40 \cr
& = 200 \times {10^{ - 4}} = 0.020 \cr} $$