If the length of a stretched string is shortened by $x \%$ and the tension is increased by $44 \%$,then the ratio of the final and initial fundamental frequencies is $2:1$. The value of $x$ is:

In contrast to annelids,the Platyhelminthes show:

Which of the following is the correct electronic configuration of $Cr$ $(Z = 24)$?

Pheromone is

Consider the following statements $A$ and $B$. Identify the correct choice in the given answer.
$A$. $p-n, p-p$ and $n-n$ forces between nucleons are not equal and charge dependent.
$B$. In a nuclear reactor,the fission reaction will be in an accelerating state if the value of the neutron reproduction factor $k > 1$.

$EMF$ of the following concentration cell will be $............$ $V$
$Cl_2(1 \ atm) | Cl^{-}(1 \ M) || Cl^{-}(0.1 \ M) | Cl_2(2 \ atm)$