The five-kingdom classification system was proposed by whom?

If $x-y+1=0$ meets the circle $x^2+y^2+y-1=0$ at $A$ and $B$,then the equation of the circle with $AB$ as diameter is

One mole of alkene $\underline{X}$ on ozonolysis gave one mole of acetaldehyde and one mole of acetone. The $IUPAC$ name of $\underline{X}$ is

Which of the following statements is not correct regarding calcination?

$A$ 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

See the diagram. The area of each plate is $2.0\ m^2$ and $d = 2 \times 10^{-3}\ m$. $A$ charge of $8.85 \times 10^{-8}\ C$ is given to plate $Q$. Then the potential of $Q$ becomes......$V$.