Portland cement is manufactured using which of the following?

$A$ steady current flows in a long wire. It is bent into a circular loop of one turn and the magnetic field at the centre of the coil is $B$. If the same wire is bent into a circular loop of $n$ turns,the magnetic field at the centre of the coil is

The mass of oxygen gas occupying a volume of $11.2 \text{ litres}$ at a temperature $27^{\circ}C$ and a pressure of $760 \text{ mm}$ of mercury in kilograms is $[$Molecular weight of oxygen $= 32]$

The area of the region bounded by the curve $y=x^{2}$ and the line $y=16$ is

If $dx + dy = (x + y)(dx - dy)$,then $\log(x + y)$ is equal to

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