If Henle's loop were absent from mammalian nephron,which of the following is to be expected?

The angular resolution of a $10\,cm$ diameter telescope at a wavelength of $5000\,\mathring{A}$ is of the order of

The mean of four observations is $3$. If the sum of the squares of these observations is $48$,then their standard deviation is

$A$ steel meter scale is to be ruled so that millimeter intervals are accurate within about $5 \times 10^{-5} \ m$ at a certain temperature. The maximum temperature variation allowable during the ruling is (Coefficient of linear expansion of steel $= 10 \times 10^{-6} \ K^{-1}$) (in $^{\circ} C$)

Which among the following complexes has square pyramidal geometry?

When an orange solution containing $Cr_2O_7^{2-}$ ions is treated with an alkali,a yellow solution is formed,and when $H^{+}$ ions are added to the yellow solution,an orange solution is obtained. Explain why this happens.