Two thermally insulated vessels 1 and 2 are filled with air at temperature (T₁, T₂), volume (V₁, V₂) and pressure (P₁, P₂) respectively. If the valve joining the two vessels is opened, the temperature inside the vessel at equilibrium will be

• A

  ${\mathrm{T}}_1+{\mathrm{T}}_2$

• B

  ${\mathrm{T}}_1{\mathrm{T}}_2\left({\mathrm{P}}_1{\mathrm{V}}_1+{\mathrm{P}}_2{\mathrm{V}}_2\right)/\left({\mathrm{P}}_1{\mathrm{V}}_1{\mathrm{T}}_1+{\mathrm{P}}_2{\mathrm{V}}_2{\mathrm{T}}_2\right)$

• C

  ${\mathrm{T}}_1{\mathrm{T}}_2\left({\mathrm{P}}_1{\mathrm{V}}_1+{\mathrm{P}}_2{\mathrm{V}}_2\right)/\left({\mathrm{P}}_1{\mathrm{V}}_1{\mathrm{T}}_2+{\mathrm{P}}_2{\mathrm{V}}_2{\mathrm{T}}_1\right)$

• D

  $\left({\mathrm{T}}_1+{\mathrm{T}}_2\right)/2$