What is formed when $PCl_3$ reacts with water?

If the angles of a triangle are in the ratio $4:1:1,$ then the ratio of the longest side to the perimeter is

If $[x]$ denotes the greatest integer not exceeding $x$ and if the function $f$ defined by $f(x)= \begin{cases} \frac{a+2 \cos x}{x^2} & , x < 0 \\ b \tan \frac{\pi}{[x+4]} & , x \geq 0 \end{cases}$ is continuous at $x=0$,then the ordered pair $(a, b)$ is equal to

As the switch $S$ is closed in the circuit shown in the figure,the current passing through it is ................ $A$.

Which of the following is the smallest gymnosperm?

The area (in sq unit) of the region bounded by the curves $2x = y^2 - 1$ and $x = 0$ is