If $(1, a)$ and $(b, 2)$ are conjugate points with respect to the circle $x^2+y^2=25$,then $4a+2b$ is equal to

The family of curves in which the sub-tangent at any point to any curve is double the abscissa is given by

In a balanced meter bridge,the resistance of the bridge wire is $0.1 \Omega/cm$. An unknown resistance $X$ is connected in the left gap and $6 \Omega$ in the right gap. The null point divides the wire in the ratio $2:3$. Find the current drawn from a battery of $5 \text{ V}$ having negligible internal resistance. (in $A$)

Which of the following organisms is not correctly matched with its taxonomic category?

If $2 \vec{a} + 3 \vec{b} + \vec{c} = \vec{0}$,then $\vec{a} \times \vec{b} + \vec{b} \times \vec{c} + \vec{c} \times \vec{a}$ is equal to

Two point charges $-q$ and $+q$ are located at points $(0, 0, -a)$ and $(0, 0, a)$ respectively. The electric potential at a point $(0, 0, z)$,where $z > a$ is