The endosperm in angiosperms develops from

$A$ tank with vertical walls is mounted so that its base is at a height $H$ above the horizontal ground. The tank is filled with water to a depth $h$. $A$ hole is punched in the side wall of the tank at a depth $x$ below the water surface. To have maximum range of the emerging stream,the value of $x$ is

Name the gas that can readily decolourise acidified $KMnO_4$ solution.

The area (in sq. units) of the region lying in the first quadrant and enclosed by the $X$-axis,the straight line $x-\sqrt{3} y=0$ and the circle $x^2+y^2=4$,is

In a $p-n$ junction diode,the thickness of the depletion layer is $2 \times 10^{-6} ~m$ and the barrier potential is $0.3 ~V$. The intensity of the electric field at the junction is:

The four distinct points $(0,0), (2,0), (0,-2)$ and $(k,-2)$ are concyclic,if $k$ is equal to