In the following circuit,the equivalent resistance between $A$ and $B$ is ...... $\Omega$.

The human hindbrain comprises three parts,one of which is:

The degree and order of the differential equation of the family of all parabolas whose axis is the $x$-axis,are respectively

$A$ plane is parallel to two lines whose direction ratios are $1, 0, -1$ and $-1, 1, 0$ and it contains the point $(1, 1, 1)$. If it cuts the coordinate axes at $A, B, C$,then the volume of the tetrahedron $OABC$ (in cubic units) is

The correct order of the $O-O$ bond length in $O_2$,$H_2O_2$ and $O_3$ is

If $\alpha, \beta$ and $\gamma$ are the lengths of the altitudes of a $\triangle ABC$ with area $\Delta$,then $\frac{\Delta^2}{R^2}\left(\frac{1}{\alpha^2}+\frac{1}{\beta^2}+\frac{1}{\gamma^2}\right)$ is equal to