An ideal gas at pressure '$$p$$' is adiabatically compressed so that its density becomes twice that of the initial. If $$\gamma=\frac{c_p}{c_v}=\frac{7}{5}$$, then final pressure of the gas is

Which one of the following statements is wrong for an isobaric process?

For a perfectly black body, coefficient of emission is

Two rods of different metals have coefficients of linear expansion '$$\alpha_1$$' and '$$\alpha_2$$' respectvely. Their respective lengths are '$$\mathrm{L}_1$$' and '$$\mathrm{L}_2$$'. At all temperatures ($$\mathrm{L}_2-\mathrm{L}_1$$) is same. The correct relation is