What is the main difference between the $P-T$ phase diagram of water and $CO_2$?

The resistances of the platinum wire of a platinum resistance thermometer at the ice point and steam point are $8 \Omega$ and $10 \Omega$ respectively. After inserting in a hot bath of temperature $400^{\circ} C$,the resistance of the platinum wire is: (in $\Omega$)

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 $R$ is a thermocouple type,then:

The thermo $e.m.f.$ produced in a thermocouple is given by the equation $E = 40\theta - \frac{\theta^2}{20}$,where $\theta$ is the temperature difference between the two junctions. The neutral temperature is ............. $^oC$.

Find the amount of heat supplied to decrease the volume of an ice-water mixture by $1 \, cm^3$ without any change in temperature. (Given: $\rho_{ice} = 0.9 \rho_{water}$,$L_{ice} = 80 \, cal/g$).

$A$ sphere of ice at $0^{\circ}C$ having initial radius $R$ is placed in an environment having ambient temperature $> 0^{\circ}C$. The ice melts uniformly,such that the shape remains spherical. After a time $t$,the radius of the sphere has reduced to $r$. Assuming the rate of heat absorption is proportional to the surface area of the sphere at any moment,which graph best depicts $r(t)$?