A cylinder has a piston at temperature of $$30 \Upsilon$$C. There is all round clearance of $$0.08 \mathrm{~mm}$$ between the piston and cylinder wall if internal diameter of the cylinder is $$15 \mathrm{~cm}$$. What is the temperature at which piston will fit into the cylinder exactly?

$$\left(\alpha_p=1.6 \times 10^{-5} / \Upsilon\mathrm{C} \text { and } \alpha_c=1.2 \times 10^{-5} / \Upsilon\mathrm{C}\right)$$

A balloon contains 1500 m$$^3$$ of He at 27$$\Upsilon$$C and 4 atmospheric pressure, the volume of He at $$-3\Upsilon$$C temperature and 2 atmospheric pressure will be