## Question

Q gas of certain mass at 273K is expanded to 81 times its vol. under adia. condition. if gamma = 1.25 for gas then its final temp. = ?

Q for a const. vol. gas thermometer one should fill gas at high temp & low pressure WHY ?

Q iF TEMP of uniform rod is slightly increase by del T its moment of inertia about 90* bisector increase BY = ? (ANS 2alpha I del T ).

Q Al sphere is dipped into H2O at 100*C if temp is increased forse of buoyancy will inc. OR decreased WHY =?

DENSITY OF A SUB. IS 10g/cc at 0*C &at 100*C d= 9.7 g/cc . coeff. of linear expantion is =?

**Joshi sir comment**

Answer : For adiabatic process TV^{γ-1 }= K

so 273*V^{0.25 }= T*(81V)^{0.25}

so 273/3 = T

Answer : Because real gases perform ideal behaviour in this range.

Answer : Inertia about perpendicular bisector = 1/12 ML^{2}

on increasing temperature by dT new inertia = 1/12 M[L(1+αdT)]^{2}

so increment in inertia = 1/12 ML^{2} [(1+αdT)^{2}-1^{-}] = 1/12 ML^{2} [ (αdT)^{2} + 2αdT ] now neglect (αdT)^{2 }because it is small term

Answer : Since temperature is already 100 degree centigrade so on increasing it further density of Al will increase rapidly in comparision to density of water so Buoyancy force will be increased.

Answer : use the formula d_{100} = d_{0 }/ (1+γ100) here γ=3α calculate α