A quantity of heat required to change the unit mass of a solid substance, from solid state to liquid state, while the temperature remains constant, is known as

  • [AIIMS 1998]
  • A

    Latent heat

  • B

    Sublimation

  • C

    Hoar frost

  • D

    Latent heat of fusion

Similar Questions

Answer the following questions based on the $P-T$ phase diagram of $CO _{2}$

$(a)\;CO _{2}$ at $1\; atm$ pressure and temperature $-60\,^{\circ} C$ is compressed isothermally. Does it go through a llquid phase?

$(b)$ What happens when $CO _{2}$ at $4\; atm$ pressure is cooled from room temperature at constant pressure?

$(c)$ Describe qualitatively the changes in a given mass of solid $CO _{2}$ at $10 \;atm$ pressure and temperature $-65\,^{\circ} C$ as it is heated up to room temperature at constant pressure.

$(d)\;CO_{2}$ is heated to a temperature $70\,^{\circ} C$ and compressed isothermally. What changes in its properties do you expect to observe?

Answer the following questions based on the $P$ - $T$ phase diagram of carbon dioxide:

$(a)$ At what temperature and pressure can the solid, liquid and vapour phases of $CO _{2}$ co-exist in equilibrium?

$(b)$ What is the effect of decrease of pressure on the fusion and boiling point of $CO _{2} ?$

$(c)$ What are the critical temperature and pressure for $CO _{2} ?$ What is their sıgnificance ?

$(d)$ Is $CO _{2}$ solid, liquid or gas at $(a)\;-70\,^{\circ} C$ under $1\; atm$, $( b )\;-60\,^{\circ} C$ under $10 \;atm,$ $(c)$ $15\,^{\circ} C$ under $56$ atm ?

During constant temperature, we feel colder on a day when the relative humidity will be ....... $\%$

A child running a temperature of $101\,^{\circ} F$ is given an antipyrin (i.e. a medicine that lowers fever) which causes an increase in the rate of evaporation of sweat from his body. If the fever is brought down to $98\,^{\circ} F$ in $20$ minutes, what is the average rate of extra evaporation caused, by the drug (in $g/min$). Assume the evaporation mechanism to be the only way by which heat is lost. The mass of the child is $30\; kg$. The spectfic heat of human body is approximately the same as that of water, and latent heat of evaporation of water at that temperature is about $580\; cal \;g^{-1}$.

Why the cooking is faster in pressure cooker ?