In a floral formula,what does the notation $(K)$ denote?

If the angles of a triangle are in the ratio $4:1:1$,then the ratio of the longest side to the perimeter is

If the coefficient of $x$ in the expansion of $\left(x^2+\frac{k}{x}\right)^5$ is $270$,then $k$ is equal to

When acetaldehyde is reacted with $LiAlH_4$,what is the product formed?

$A$ steady current flows in a long wire. It is bent into a circular loop of one turn and the magnetic field at the centre of the coil is $B$. If the same wire is bent into a circular loop of $n$ turns,the magnetic field at the centre of the coil is

Which of the following statements does not form part of Bohr's model of the hydrogen atom?