In the environment,ozone is known for its

The $T.V.$ transmission tower in Delhi has a height of $245 \ m$. The distance up to which the broadcast can be received (taking the radius of earth to be $6.4 \times 10^6 \ m$) is........$km$ :

If the harmonic mean between the roots of $(5+\sqrt{2}) x^2-b x+(8+2 \sqrt{5})=0$ is $4$,then the value of $b$ is

Which substance is used as a gaseous insulator in high-voltage generators?

Organisms that are phenotypically similar but genotypically different are said to be

Opening of flowers in the cymose inflorescence is