Thermal properties of matter practice · Medium

If between wavelength $\lambda$ and $\lambda + d\lambda ,{e_\lambda }$ and ${a_\lambda }$ be the emissive and absorptive powers of a body and ${E_\lambda }$ be the emissive power of a perfectly black body, then according to Kirchoff’s law, which is true

Assertion (A): Reading of temperature may be same on Fahrenheit and Kelvin scale.
Reason (R): Size of degree is equal on Fahrenheit and Kelvin scale.

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

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

Statement 1: When two liquid samples of different masses with temperatures $T_1$ and $T_2 \,\left(T_1 < T_2\right)$ but same specific heats are mixed the equilibrium temperature of the mixture is $\frac{T_1+T_2}{2}$
Statement 2: The amount of heat lost by the hotter liquid is equal to the amount of heat absorbed by the cooler liquid.

Two temperature scales A and B are related by $\frac{{A - 42}}{{110}}$ = $\frac{{B - 72}}{{220}}$. At which temperature two scales have the same reading?

Statement-I: To have same difference between the lengths of two metallic rods their initial lengths of $0^{\circ} \mathrm{C}$ should be in the inverse ratio of their coefficient of linear expansion.
Statement-II: If the lengths of two metallic rods at $0^{\circ} \mathrm{C}$ are in the inverse ratio of their coefficient of linear expansion then the change in the lengths due to same rise of temperature is same.

A spring of force constant $'K'$ is cut into two pieces such that one piece is three times the length of the other. The longer piece will have a force constant of

Assertion (A): $P V / T=$ constant for 1 gram of gas. This constant varies from gas to gas
Reason (R): I gram of different gases at NTP occupy different volumes

It is hotter for the same distance over the top of a fire than it is in the side of it, mainly because

At a common temperature, a block of wood and a block of metal feel equally cold or hot. The temperature of block of wood and block of metal are

In van der Wall equation $\left[P+\frac{a}{V^2}\right][V-b]=R T ; P$ is pressure, $V$ is volume, $R$ is universal gas constant and $T$ is temperature. The ratio of constants $\frac{a}{b}$ is dimensionally equal to:

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

Liquid is filled in a vessel which is kept in a room with temperature ${20^0}C$ . When the temperature of the liquid is ${80^0}C$, then it loses heat at the rate of 60 cal/s. What will be the rate of loss of heat when the temperature of the liquid is ${40^0}C$

The luminosity of the Rigel star is 17000 times that of the sun. Assume both to be perfectly black bodies. If the surface temperature of the sun is 6000 K, then the temperature of the star is

1 g of steam at ${100^\mathrm{o}}C$ melts how much ice at ${0^\mathrm{o}}C$ [Latent heat of ice = 80 col/gm] and latent heat of steam = 540 cal/gm]

A rod of silver at ${0^0}C$ is heated to ${100^0}C$ . It’s length is increased by 0.19 cm. Coefficient of cubical expansion of the silver rod is

Assertion (A): At constant temperature, when pressure of a gas is increased by $10 \%$, then volume decreases by less than $10 \%$
Reason (R): At constant temperature the volume of gas is inversely proportional to the pressure acting on it.

The maximum energy in thermal radiation from a source occurs at the wavelength 4000${A^0}$. The effective temperature of the source is

At some temperature $T,$ a bronze pin is a little large to fit into a hole drilled in a steel block. The change in temperature required for an exact fit is minimum when

Assertion (A): In summer, the pendulum clock runs slow.
Reason (R): As temperature increases, length of the pendulum decreases and time period decreases.

The temperature of a substance increases by ${27^0}C$. On the Kelvin scale this increase is equal to

No other thermometer is as suitable as a platinum resistance thermometer to measure temperature in the entire range of

One quality of a thermometer is that its heat capacity should be small. If $P$ is a mercury thermometer, $Q$ is a resistance thermometer and $R$ thermocouple type then

On a new scale of temperature (which is linear) and called the scale, the freezing and boiling points of water are ${39^\mathrm{o}}W$ and ${239^\mathrm{o}}W$ respectively. What will be the temperature on the new scale, corresponding to a temperature of ${39^\mathrm{o}}C$ on the Celsius scale

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

On heating, the temperature at which water has minimum volume is

The temperature, at which Centigrade and Fahrenheit scales give the same reading is

Assertion (A): When a Bimetallic strip made up of brass and iron is heated then brass lies on the convex side.
Reason (R): Due to lower value of coefficient of linear expansion, brass acquires convex shape.

Two thermometers $A$ and $B$ are exposed in sun light. The valve of is pointed black, but that of $B$ is not pointed. The correct statement regarding this case is