The number of gram atoms of oxygen present in $0.3 \, mole$ of $(COOH)_2 \cdot 2H_2O$ is

$ABC$ is a triangular plate of uniform thickness. The sides are in the ratio $3:4:5$ as shown in the figure. $I_{AB}, I_{BC}, I_{CA}$ are the moments of inertia of the plate about axes $AB, BC$ and $CA$ respectively. Which one of the following relations is correct?

Two wires of the same material have lengths in the ratio $1:2$ and their radii are in the ratio $1:\sqrt{2}$. If they are stretched by applying equal forces,the increase in their lengths will be in the ratio:

$\int_{-2}^2 |[x]| \, dx$ is equal to

Which of the following compounds will be most easily attacked by an electrophile?

If the direction ratios $(l, m, n)$ of two lines satisfy the equations $l+m+n=0$ and $mn-2ln+lm=0$,then the angle between the lines is