Questions

A manometer is used to measure a pressure difference between two points.

Cohesion refers to attraction between molecules of the same kind while adhesion refers to attraction between different kinds of molecules

Euclid of Alexandria was a Greek mathematician, often referred to as the Father of Geometry.

Parabola, because when the coin is dropped at a particular point, it has the same velocity as the running train. So by Newton's first law, it continues its motion horizontally with that velocity. But then, it is also pulled down by earth's gravity continuously. In this situation its horizontal motion gives way to the parabolic motion until it reaches the ground.

Electronegativity is the tendency for an atom to attract electrons. There are general trends on the periodic table which you can use to determine the relative electronegativity for different elements, but otherwise you can also look at their valence shell and effective nuclear charge to determine their relative electronegativity.

Here from the given options, Lithium has least tendency to attract electrons and thus has a lower electronegativity.