Why is there a shortage of water even though it occupies about `71%` of the earth's surface ?

How is sea or ocean water useful to us, even though it is salty?

In the combined form, dihydrogen constitues about ______ % of the earth's crust.

If the earth suddenly contracts so that its radius reduces by 4% with mass remaining same, then what will happen to the escape velocity from earth's surface now?

Why is H_2 stable even though it never satisfies the octet rule ?

If the radius of the earth were to shrink by 1% its mass remaining the same, the acceleration due to gravity on the earth's surface would

Questions based on paragraph : Earthquakes refers to sudden vibrations on the Earth's surface and shaking of the earth . This leads to generation of seismic waves causing tremors or shaking of Earth's surface . The focal point of earthquake is the point below the epicenter on the earth surface . the major loss occurs near the area where strong convulsions or waves first reach the epicenter . earthquakes can be mild , uauslly occuring in larger numbers of intensified ( acute) , occuring rarely . the magnitude of the earthquake is measured in richter scale . : Based on the given paragraph answer the following questions : Name two modern equipments used to get prior intimation about earthquake .

The height of a communication satellite from the earth's surface is about

Give reasons : Why is mercury preferred over water in making thermometers even though both of them have similar coefficient of volume expansion ?

Use your brain power! Why does the pitcher plant feed on insects even though it produces food by photosynthesis?