Two rods of the same length and material transfer a given amount of heat in $12 \, s$,when they are joined in parallel. But when they are joined in series,then they will transfer the same amount of heat under the same conditions in ......... $s$.

In $Anthoceros$,vegetative reproduction occurs by which of the following?

Find the values of $x$,if: $(i)$ $\left|\begin{array}{ll}2 & 4 \\ 5 & 1\end{array}\right|=\left|\begin{array}{cc}2 x & 4 \\ 6 & x\end{array}\right|$ (ii) $\left|\begin{array}{ll}2 & 3 \\ 4 & 5\end{array}\right|=\left|\begin{array}{ll}x & 3 \\ 2 x & 5\end{array}\right|$

$AB$ is an ionic solid. The ionic radii of $A^{+}$ and $B^{-}$ are respectively $r_c$ and $r_a$. Lattice energy of $AB$ is proportional to :

The area (in square units) of the region bounded by $x^2=8y$,$x=4$ and the $X$-axis is:

Which one of the following statements is wrong?