Thermal properties of matter practice · Medium

When a bimetallic strip made of iron $\left( {{\alpha _1}} \right)$ and copper $\left( {{\alpha _2}} \right)$ is heated $\left( {{\alpha _2} > {\alpha _1}} \right)$

A hot body will radiate heat most rapidly if its surface is

A gas at the temperature $250\;K$ is contained in a closed vessel. If the gas is heated through $1K,$ then the percentage increase in its pressure will be

Statement-I: A thin rod and a thick rod made of same material having same length are heated through same range of temperature. Then both the rods expand equally.
Statement-II: The linear expansion $e=l \alpha \Delta t$

The pressure measured by a constant volume gas thermometer is $40 \mathrm{kPa}$ at the triple point of water. What will be the pressure measured at the boiling point of water $\left(100^{\circ} \mathrm{C}\right)$ ?

Identify the pair of physical quantities which have different dimensions.

Calorimeters are made of which of the following

(A): A brass tumbler feels much colder than a wooden tray on a chilly day.
(R): The thermal conductivity of brass is less than that of wood.

(A): The specific heat capacity of a given solid can be determined by using the principle of calorimetry.
(R): Heat gained is equal to the heat lost

In which of the following heat loss is primarily not due to convection?

The ends of 2 different materials with their thermal conductivities, radii of cross section and length all in the ratio of $1\;:2$ maintained at temperature difference. If the rate of the flow of heat in the longer rod is 4 cal${\mathrm{s}^{ - 1}}$, that in the shorter rod in cal${\mathrm{s}^{ - 1}}$ will be

Maximum density of ${H_2}O$ is at the temperature

Assertion (A): Real gases behave like an ideal gas at low densities
Reason (R): At low densities interaction between molecules in a gas is less

The temperature on Celsius scale is ${25^\mathrm{o}}C$. What is the corresponding temperature on the Fahrenheit scale

Statement A: Thermal radiations are electromagnetic radiation with wave lengths greater than visible light.
Statement B: Thermal radiations can propagate through vacuum.

On the Celsius scale the absolute zero of temperature is at

If a ball of $70 \mathrm{~kg}$ mass hits an ice cube and temperature of ball is $100^{\circ} \mathrm{C}$, then how much ice converted into water? (Specific heat of ball is $0.2 \mathrm{~cal} \mathrm{~g}^{-1}$, Latent heat of ice $=80 \mathrm{~cal} \mathrm{~g}^{-1}$)

On a hilly region, water boils at ${95^0}C$.The temperature expressed in Fahrenheit is

An icebox made of $1.5 \mathrm{~cm}$ thick styrofoam has dimensions $60 \mathrm{~cm} \times 60 \mathrm{~cm} \times 30 \mathrm{~cm}$. It contains ice at $0^{\circ} \mathrm{C}$ and is kept in a room at $40^{\circ} \mathrm{C}$. Find the rate at which the ice is melting. Latent heat of fusion of ice $=3.36 \times 10^5 \mathrm{~J} \mathrm{~kg}^{-1}$. and thermal conductivity of styrofoam $=0.04 \mathrm{~W} \mathrm{~m}^{-1}{ }^{\circ} \mathrm{C}^{-1}$.

A brass disc fits simply in a hole of a steel plate. The disc from the hole can be loosened if the system

Statement-I: When a bimetallic strip made of iron and brass is heated then it bends in the form of concave towards Brass.
Statement-II: The coefficient of linear expansion of iron is less than brass.

Statement I: A special type of thermometer (used to measure very high temperatures and calibrated for an ideal black body) measures a value lower than the actual value of the temperature of a red hot iron piece kept in open.

Statement II: As the iron piece is kept in open, it loses its heat.

With rise in temperature, density of a given body changes according to one of the following relations

A beaker is completely filled with water at ${4^0}C$. It will overflow

Calculate the force required to prevent a steel wire of $1 \mathrm{~mm}^2$ cross-section from contracting when it cools from $60^{\circ} \mathrm{C}$ to $15^{\circ} \mathrm{C}$, if Young's modulus for steel is $2 \times 10^{11} \mathrm{~Nm}^{-2}$ and its coefficient of linear expansion is $0.000011^{\circ} \mathrm{C}^{-1}$.

A spherical ball of surface area $20 \mathrm{~cm}^2$ absorbs any radiation that falls on it. It is suspended in a closed box maintained at $57^{\circ} \mathrm{C}$. (a) Find the amount of radiation falling on the ball per second. (b) Find the net rate of heat flow to or from the ball at an instant when its temperature is $200^{\circ} \mathrm{C}$. Stefan constant $=6.0 \times 10^{-8}$ $\mathrm{W} \mathrm{m}{ }^{-2} \mathrm{~K}^{-4}$.

Assertion(A): Good conductors of electricity are also good conductors of heat.

Reason(R): In good conductors of electricity, there are large numbers of free electrons.

Which of the following statements are true
(a) Rubber contracts on heating
(b) Water expands on freezing
(c) Water contracts on heating from $0^{\circ} \mathrm{C}$ to $4^{\circ} \mathrm{C}$
(d) Water expands on heating from $4^{\circ} \mathrm{C}$ to $40^{\circ} \mathrm{C}$

Heat is flowing through a rod of length $25.0 \mathrm{~cm}$ having cross-sectional area $8.80 \mathrm{~cm}^2$. The coefficient of thermal conductivity for the material of the rod is $K=9.2 \times 10^{-2} \mathrm{~kcal} \mathrm{~s}^{-1} \mathrm{~m}^{-1}{ }^{\circ} \mathrm{C}^{-1}$. The temperatures of the ends of the rod are $125^{\circ} \mathrm{C}$ and $0^{\circ} \mathrm{C}$ in the steady state. Calculate temperature of a point at a distance of $10.0 \mathrm{~cm}$ from the hot end.

In a surrounding medium of temperature $10^{\circ} \mathrm{C}$, a body takes $7 \mathrm{~min}$ for a fall of temperature from $60^{\circ} \mathrm{C}$ to $40^{\circ} \mathrm{C}$. In what time the temperature of the body will fall from $40^{\circ} \mathrm{C}$ to $28^{\circ} \mathrm{C}$ ?