Thermal properties of matter practice · Mixed difficulty

A barometer with a brass scale correct at $0^\circ C$ reads 70 cm of mercury on a day when the air temperature is $40^\circ C$. The correct reading at $0^\circ C$ is [Coefficient of real expansion of mercury is $0.00018/^\circ C$ and the coefficient of linear expansion of brass is $0.000018/^\circ C$ ]

A body temperature is change $90^{\circ} \mathrm{C}$ to $60^{\circ} \mathrm{C}$ in 5 minutes then find out the taken time when its is change $60^{\circ} \mathrm{C}$ to $30^{\circ} \mathrm{C}$ when temperature of surrounding is $20^{\circ} \mathrm{C}$.

Select correct statement related to heat

Assertion: A good absorber is a good emitter.
Reason: For a substance, absorbance is equal to emissivity.

In two same dimensional vessels same amount and same temperature ice is filled. If in both vessels complete ice is melt in 20 $\mathrm{min}$ and $50 \mathrm{~min}$ then find out the ratio of thermal conductivity of both vessels.

A piece of blue glass heated to a high temperature and a piece of red glass at room temperature, are taken inside a dimly lit room then

In which mode of transmission, the heat waves travel along straight line with the speed of light?

Mercury is often used in clinical thermometers. Which one of the following properties of mercury is not a reason for this?

On heating one end of a rod, the temperature of whole rod will be uniform when :-

Four rods of silver, copper, brass and wood are of same shape. They are heated together after wrapping a paper on it, the paper will burn first on

Critical temperature can be defined as the

Good absorbers of heat are

Two identical plates of different metals are joined to form a single plate whose thickness is double the thickness of each plate. If the coefficients of conductivity of each plate are 2 and 3 respectively, then the conductivity of composite plate will be

At NTP water boils at ${100^0}C$. Deep down the mine, water will boil at a temperature

Four pieces of iron heated in a furnace to different temperatures show different colours listed below. Which one has the highest temperature

A piece of platinum can be sealed successfully into soda glass but not a piece of copper because

Statement A: Heat transfer by conduction and convection require a material medium.
Statement B: Heat transfer by radiation doesn't effect the medium through which it passes.

By what percentage should the pressure of a given mass of a gas be increased so as to decrease its volume by $20 \%$ at constant temperature?

Which of the following pairs is wrong

Two thermometers are constructed in the same way except that one has a spherical bulb and the other a cylindrical bulb; which one will respond quickly to temperature changes

The coefficient of linear expansion of brass and steel are ${\alpha _1}$ and ${\alpha _2}$. If we take a brass rod of length ${l_1}$ and steel rod of length ${l_2}$ at ${0^0}C$, their difference in length $\left( {{l_2} - {l_1}} \right)$ will remain the same at a temperature if

The latent heat of vaporisation of a substance is always

Rate of transfer of heat is maximum in the case of

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 $e=l \alpha \Delta t$

Among the following rods made of same material, the one that can conduct more heat in a given time when their ends are maintained at the same temperature differences

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 $\gamma=\alpha_x+\alpha_y+\alpha_z$.

Two metallic wires of identical dimensions are connected in series. If $\sigma_1$ and $\sigma_2$ are the conductivities of these wires respectively, the effective conductivity of the combination is :

Assertion (A): Steel rods are used in R.C.C
Reason (R): Both steel and R.C.C have almost same values of coefficient of linear expansion.

The density of mercury is $13.6 \mathrm{~g} \mathrm{~cm}^{-3}$ at $0^{\circ} \mathrm{C}$ and its coefficient of cubical expansion is $1.82 \times 10^{-4}{ }^{\circ} \mathrm{C}^{-1}$. Calculate the density of mercury at $50^{\circ} \mathrm{C}$.

Assertion (A): Pressure of gas is same everywhere inside a closed container
Reason (R): The gas molecules undergo elastic collisions among themselves and also with the walls