An ideal gas is heated from $27^{\circ} \mathrm{C}$ to $627^{\circ} \mathrm{C}$ at constant pressure. If initial volume of gas is $4 \mathrm{~m}^3$, then the final volume of the gas will be
A large insulated sphere of radius ' $r$ ', charged with ' $Q$ ' units of electricity, is placed in contact with a small insulated uncharged sphere of radius ' R ' and is then separated. The charge on the smaller sphere will now be
A thin concavo-convex lens with convex face receiving incident rays has radii of curvatures 12 cm and 24 cm respectively. If refractive index of material of lens is 1.5 , then the focal length of the lens is
At two points on a horizontal tube of varying cross-section the radii are 1 cm and $\mathbf{0 . 4 ~ c m}$, velocities of fluid are $\mathrm{V}_1, \mathrm{~V}_2$ and pressure difference ( $P_1-P_2$ ) between these points is 4.9 cm of water. The value of $\sqrt{V_2^2-V_1^2}$ is ( $\mathrm{g}=$ acceleration due to gravity $\mathrm{g}=980 \mathrm{~cm} / \mathrm{s}^2$ )