Thermal properties of matter practice · Mixed difficulty

At $0^{\circ} \mathrm{C}$, the densities of a cork and a liquid in which the cork floats are $\mathrm{d}_1$ and $\mathrm{d}_2$ respectively. The coefficients of expansion for the material of the cork and the liquid are $\gamma$ and $100 \gamma$ respectively. If the cork sinks when temperature of liquid is $\mathrm{t}^{\circ} \mathrm{C}$, then ratio $\left(\mathrm{d_2 / d}_1\right)$ is

How many grams of ice at $-14^{\circ} \mathrm{C}$ are needed to cool $200 \mathrm{~g}$ of water from $25^{\circ} \mathrm{C}$ to $10^{\circ} \mathrm{C}$ ? Take specific heat of ice $=0.5 \mathrm{cal} / \mathrm{g} /{ }^{\circ} \mathrm{C}$ and latent heat of ice $=80 \mathrm{cal} / \mathrm{g}$.

During process of melting, thermal energy that is absorbed during process of melting is called:

S.I. unit of universal gas constant is

A composite rod made of copper ($\alpha = 1.8 \times {10^{ - 5}}{\mathrm{K}^{ - 1}}$) and steel ($\mathrm{\alpha } = 1.2 \times {10^{ - 5}}{\mathrm{K}^{ - 1}}$) is heated. Then

(A): It is hotter over the top of a fire than at the same distance on the sides.
(R): Air surrounding the fire conducts more heat upwards.

When two ends of a rod wrapped with cotton are maintained at different temperatures and after same time every point of the rod attains a constant temperature, then

The lower and upper fixed points in Reaumur scale is

When a rod is heated but prevented from expanding, the stress developed is independent of

Statement-I: The linear coefficients of expansion of a crystal along three perpendicular axes are $\alpha, \frac{-\alpha}{2}, \frac{\alpha}{5}.$ Its volume coefficient is $\frac{7 \alpha}{10}$
Statement-II: For anisotropic solids $\gamma=\alpha_x+\alpha_y+\alpha_z$.

A steel wire of uniform area $2\,\,m{m^2}$ is heated up to ${50^0}C$ and is stretched by tying its ends rigidly. The change in tension when the temperature falls from ${50^0}C$ to ${30^0}C$ is (Take $Y = 2 \times {10^{11}}N{m^{ - 2}},\alpha = 1.1 \times {10^{ - 5}}^0{C^{ - 1}})$

A $30.0 \mathrm{~cm}$ long metal rod expands by $0.0650 \mathrm{~cm}$ when its temperature is raised from $0^{\circ} \mathrm{C}$ to $100^{\circ} \mathrm{C}$. A second rod of different metal and of the same length expands by $0.0350 \mathrm{~cm}$ for the same rise in temperature. A third composite rod, also $30.0 \mathrm{~cm}$ long, is made-up of pieces of each of the above metals placed end to end and expands by $0.0580 \mathrm{~cm}$ when temperature is increased from $0^{\circ} \mathrm{C}$ to $100^{\circ} \mathrm{C}$. Find the length of the smaller portion of the composite bar (in $\mathrm{cm}$) at $0^{\circ} \mathrm{C}$.

The maximum wavelength in the energy distribution spectrum of sun is $4753\,\,\mathop {\text{A}}\limits^ \circ$ and its temperature is $6050 \mathrm{~K}$. The temperature of star whose energy distribution shows a maximum at $9506\,\,\mathop {\text{A}}\limits^ \circ$ is

A metal sphere of radius $r$ and specific heat $c$ is rotated about an axis passing through its centre at a speed of $n$ rotations per second. It is suddenly stopped and 50% of its energy is used in increasing its temperature. Then the rise in temperature of the sphere is

A metallic solid sphere is routing about its diameter as axis of rotation. If the temperature is increased by 200℃, the percentage in its moment of inertia is (Coefficient of linear expansion of the metal$= {10^{ - 5}}^0{C^{ - 1}}$)

Ice, water and steam co-exist at triple point temperature 273.16K and pressure 4.6mm Hg. In a system in which the triple point conditions of temperature and pressure exist, the pressure is increased a little while keeping the temperature constant, then the system contains

Two metal strips that constitute a thermostat must necessarily differ in their

A perfect black body is one whose emissive power is

If the volume of a block of metal changes by $0.12 \%$, when it is heated through $20^{\circ} {C}$, then the coefficient of areal expansion is :

Statement-I: Two rods of the same material have the same lengths but diameter are in the ratio of $1:2.$ If $1000 \mathrm{cal}$ of heat is supplied to the two rods separately the ratio of their linear expansion is $4:1.$
Statement-II: The linear expansion $e=l \alpha \Delta t$

The standard fixed point for temperature measurements in use today is

A centigrade and a Fahrenheit thermometer are dipped in boiling water. The water temperature is lowered until the Fahrenheit thermometer registers ${140^0}$. What is the fall in temperature as registered by the Centigrade thermometer

Identify the pair of physical quantities which have different dimensions.

A metal ball immersed in alcohol weighs ${W_1}$ at ${0^ \circ }C$ and ${W_2}$ at ${59^ \circ }C$. The coefficient of cubical of cubical expansion of the metal is less than that of alcohol. Assuming that the density of the metal is large compared to that of alcohol, it can be shown that

In the relation $n = \frac{{PV}}{{RT}},n =$

Colour of shinning bright star is an indication of its

A metal ball immersed in water weights ${w_1}\;\mathrm{at}\;{0^ \circ }\mathrm{C and}\;{w_2}\;$ at 50$^ \circ C$. The coefficient of cubical expansion of metal is less than that water. Then

Two black bodies at $327^\circ C\,\,\mathrm{and}\,\,627^\circ C$ are suspended in an environment at $27^\circ C.$ The ratio of their emissive powers is

A gas in an airtight container is heated from ${25^0}C$ to ${90^0}C$ The density of the gas will