$X$ and $Y$ are two metals. When burnt in air,$X$ forms only oxide while $Y$ forms oxide and nitride. The metals $X$ and $Y$ may be

$A$ circle with center at $(2,4)$ is such that the line $x+y+2=0$ cuts a chord of length $6$. The radius of the circle is

If the equation $12x^2 + 7xy - py^2 - 18x + qy + 6 = 0$ represents a pair of perpendicular straight lines,then

Two electric charges of $9 \mu C$ and $-3 \mu C$ are placed $0.16 \ m$ apart in air. There will be a point $P$ on the line joining the two charges and in between them where the electric potential is zero. The distance of $P$ from the $9 \mu C$ charge is (in $m$)

Which of the following acids is a vitamin?

The chief water conducting elements of xylem in gymnosperms are