The binding energies of nuclei $X$ and $Y$ are $E_1$ and $E_2$ respectively. Two atoms of $X$ are fused to give one atom of $Y$ and an energy $Q$ is released. Then

If the equation $x^2+2 \sqrt{2} xy+2y^2+4x+4 \sqrt{2}y+1=0$ represents a pair of parallel straight lines,find the distance between them.

In a rectangle $ABCD$ where $BC = 2AB$,the moment of inertia will be minimum about which axis?

The most appropriate magnetization $M$ versus magnetising field $H$ curve for a paramagnetic substance is

$A$ $U$-tube has a left limb with a cross-sectional area that is one-quarter of the right limb. The tube contains mercury (density $13.6 \ g/cm^3$). The level of mercury in the narrow left limb is at a distance of $36 \ cm$ from the upper end of the tube. What will be the rise in the level of mercury in the right limb if the left limb is filled to the top with water (in $cm$)? (Density of water = $1 \ g/cm^3$)

Which of the following is an example of Disciflorae?