Which of the following oxides will not react with $NaOH$?

Data Entry - Physics

Identify the major product formed when $2-$Methylhexan$-3-$ol is heated with concentrated sulphuric acid.

$A$ metal rod of length $2 \text{ m}$ has cross-sectional areas $2A$ and $A$ as shown in the figure. The ends are maintained at temperatures $100^{\circ}\text{C}$ and $70^{\circ}\text{C}$. The temperature at the middle point $C$ is...... $^{\circ}\text{C}$

$A$ convex lens is made up of three different materials as shown in the figure. For a point object placed on its axis,the number of images formed is:

More than $70\%$ of the world's freshwater is contained in: