Which of the following aqueous solutions will exhibit the highest boiling point?

If the mean and variance of a binomial variate $X$ are $8$ and $4$ respectively,then $P(X < 3)$ equals to

If a body dropped freely from a height of $20 ~m$ reaches the surface of a planet with a velocity of $31.4 ~ms^{-1}$,then the length of a simple pendulum that ticks seconds on the planet is (in $~m$)

If the harmonic mean of the roots of the equation $\sqrt{2}x^2 - bx + (8 - 2\sqrt{5}) = 0$ is $4$,then the value of $b$ is:

If the normal to the curve $y=f(x)$ at the point $(3,4)$ makes an angle of $\frac{3 \pi}{4}$ with the positive $X$-axis,then the value of $f^{\prime}(3)$ is

If $\Delta U$ and $\Delta W$ represent the increase in internal energy and work done by the system respectively in a thermodynamic process,which of the following is true?