$A$ wire suspended vertically from one of its ends is stretched by attaching a weight of $200 \ N$ to the lower end. The weight stretches the wire by $1 \ mm$. The elastic energy stored in the wire is ......... $J$.

If there is an error of $\pm 0.04 \text{ cm}$ in the measurement of the diameter of a sphere, then the approximate percentage error in its volume, when the radius is $10 \text{ cm}$, is

The compound formed on heating chlorobenzene with chloral in the presence of concentrated sulphuric acid is:

The value of $\cos 15^{\circ} \cos 7.5^{\circ} \sin 7.5^{\circ}$ is

Which of the following inhibits leaf abscission?

In a $500 \ mL$ capacity vessel,$CO$ and $Cl_2$ are mixed to form $COCl_2$. At equilibrium,it contains $0.2 \ mole$ of $COCl_2$ and $0.1 \ mole$ of each of $CO$ and $Cl_2$. The equilibrium constant $K_c$ for the reaction,$CO(g) + Cl_2(g) \rightleftharpoons COCl_2(g)$ is: