An electric kettle (rated accurately at $2.5\, kW$) is used to heat $3\, kg$ of water from $15\,^oC$ to boiling point. It takes $9.5$ minute. Then, the amount of heat that has been lost is

A thermally insulated vessel contains some water at $0^0C$. The vessel is connected to a vacuum pump to pump out water vapour. This results in some water getting frozen. It is given Latent heat of vaporization of water at $0^o C =21 × 10^5 J/kg$ and latent heat of freezing of water $= 3.36 × 10^5 J/kg$. The maximum percentage amount of water that will be solidified in this manner will be ...... $\%$

One kilogram of ice at $0°C$ is mixed with one kilogram of water at $80°C.$ The final temperature of the mixture is........ $^oC$

$($Take : specific heat of water$ = 4200\,J\,k{g^{ - 1}}\,{K^{ - 1}}$, latent heat of ice $ = 336\,kJ\,k{g^{ - 1}})$

Three liquids with masses ${m_1},\,{m_2},\,{m_3}$ are thoroughly mixed. If their specific heats are ${c_1},\,{c_2},\,{c_3}$ and their temperatures ${T_1},\,{T_2},\,{T_3}$ respectively, then the temperature of the mixture is

We have half a bucket $(6l)$ of water at $20\,^oC$  . If we want water at $40\,^oC$, how much steam at $100\,^oC$ should be added to it ?

If mass energy equivalence is taken into account, when water is cooled to form ice, the mass of water should