Which of the following statements is correct?

$A$ uniform cylinder of length $L$ and mass $M$ having cross-sectional area $A$ is suspended,with its length vertical,from a fixed point by a massless spring such that it is half-submerged in a liquid of density $\sigma$ at equilibrium position. The extension $x_0$ of the spring when it is in equilibrium is:

Guard cells are helpful in:

What is the product obtained from the oxidation of isopropyl alcohol?

The area (in square units) of the triangle formed by the points with polar coordinates $(1, 0)$,$(2, \frac{\pi}{3})$,and $(3, \frac{2\pi}{3})$ is

If vapour pressures of pure liquids $A$ and $B$ are $300 \ torr$ and $800 \ torr$ respectively at $25 \ ^oC$. When these two liquids are mixed at this temperature to form a solution in which mole percentage of $B$ is $92$,then the total vapour pressure is observed to be $0.95 \ atm$. Which of the following is true for this solution?