Thermal properties of matter practice · Mixed difficulty

Assertion(A): Water vapours at $100^{\circ} \mathrm{C}$ will burn you more than water at $100^{\circ} \mathrm{C}$.

Reason(R): Heat required to convert total mass of any substance from one state to another state is called latent heat.

What extinguishes a fire most quickly?

Assertion: Animals curl into a ball, when they feel very cold.
Reason: Animals by curling their body reduce the surface area.

The radius of a metal sphere at room temperature, ${T}$ is ${R}$ and the co-efficient of linear expansion of metal is $\alpha$. The sphere is heated a little by a temperature $\Delta {T}$ so that its new temperature is $T+\Delta T$. The increase in the volume of the sphere is approximately

Assertion: A beaker is completely filled with water at $4^{\circ} \mathrm{C}$. It will overflow, both when heated or cooled.
Reason: There is expansion of water below and above $4^{\circ} \mathrm{C}$.

Assertion: If a gas container in motion is suddenly stopped, the temperature of the gas rises.
Reason: In given process the kinetic energy of ordered mechanical motion is converted into the kinetic energy of random motion of gas molecules.

The numerical value of coefficient of linear expansion is independent of units of
a) Length
b) Temperature
c) Area
d) Mass

If the sun’s surface radiates heat at $6.3 \times {10^7}W{m^{ - 2}}$. Calculate the temperature of the sun assuming it to be a black body $\left( {\sigma = 5.7 \times {{10}^{ - 8}}W{m^{ - 2}}{K^{ - 4}}} \right)$

Newton’s law of cooling is used in laboratory for the determination of the

If $\alpha, \beta$ and $\gamma$ are coefficients of linear, superficial and volume expansion respectively, then :

At what temperature is the Fahrenheit scale reading equal to half that on the Celsius scale.

The temperature of a wire is doubled. The Young’s modulus of elasticity

Consider a compound slab consisting of two different materials having equal lengths, thicknesses, cross section and thermal conductivities ${K}$ and $2{K}$ respectively, are connected in series. The equivalent thermal conductivity of the slab is

(A): Snow is better insulator than ice.
(R): Snow contain air packet and air is good insulator of heat

Assertion (A) : A glass of water is filled at $4^{\circ} \mathrm{C}$. Water will overflow, if temperature is increased or decreased. (Ignore expansion of glass).

Reason (R) : Density of water is minimum at $4^{\circ} \mathrm{C}$.

Assertion (A): For best contrast between maxima
and minima in the interference pattern of Young's
double slit experiment, the intensity of light
emerging out of the two slits should equal.
Reason (R): The intensity of interference pattern
is directly proportional to the square of amplitude.

The pressure is exerted by the gas on the walls of the container because

A gas at ${27^0}C$ and pressure of 30 atm is allowed to expand to atmosphere pressure and volume 15 times larger. The final temperature of the gas is?

The temperature at which a black body ceases to radiate energy, is

If $K$ and $\sigma$ respectively are the thermal and electrical conductivities of a metal at absolute temperature $T$, then

When $p$ calories of heat is given to a body, it
absorbs $q$ calories. Then the absorption
power of body will be

In case of a perfect black body

If reflecting and transmitting powers of a body are 0.2 and 0.3 units, then its absorptive power will be

A piece of glass is heated to a high temperature and then allowed to cool. If it cracks, a probable reason for this is the following property of glass

Two lead spheres at the same temperature have radii in the ratio $1: 2$. What is the ratio of their heat capacities?

Distribution of energy in the spectrum of a black body can be correctly represented by

Two spheres of the same material have the same radius but one is hollow while the other is solid. Both spheres are heated to same temperature. Then:

Assertion (A) : A solid sphere and a hollow sphere of same material and same radius are kept at same temperatures in atmosphere. Rate of cooling of hollow sphere will be more.

Reason (R) : If all other conditions are same, then rate of cooling is inversely proportional to the mass of body.

Assertion: Rubber contract on heating.
Reason: In rubber as temperature increases, the amplitude of transverse vibrations increases more than the amplitude of longitudinal vibrations.

Which of the following is the example of ideal black body