Water in a river $20 \ m$ deep is flowing at a speed of $10 \ ms^{-1}$. The shearing stress between the horizontal layers of water in the river in $Nm^{-2}$ is (Coefficient of viscosity of water $= 10^{-3} \ SI$ units).

When one end of a capillary tube is dipped in water,the height of the water column is $h$. The upward force of $105 \text{ dyne}$ due to surface tension is balanced by the force due to the weight of the water column. What is the inner circumference of the capillary (in $\text{ cm}$)? (Surface tension of water $= 7 \times 10^{-2} \text{ N m}^{-1}$)

The technique used to make numerous copies of a specific segment of $DNA$ quickly and accurately is

Which of the following is the pair of biofertilizers?

If the difference between the roots of the equations ${x^2} + ax + b = 0$ and ${x^2} + bx + a = 0$ is the same,and $a \ne b$,then:

The formula of the product formed when sodium thiosulphate solution is added to silver bromide is: