$A$ $TV$ transmitter has a range of $50 \ km$. The height of the $TV$ transmitter is . . . . . . (Radius of the earth,$R_e = 6.4 \times 10^6 \ m$). (in $m$)

$A$ small sphere oscillates simple harmonically in a watch glass whose radius of curvature is $1.6 \ m$. The period of oscillation of the sphere in seconds is (acceleration due to gravity,$g = 10 \ m/s^2$). (in $\pi$)

In agarose gel electrophoresis,$DNA$ molecules are separated on the basis of their

Pseudocoelom develops from

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:

Which of the following is the correct order of solubility of alkaline earth metal sulfates in water?