Questions

Force of impact is the force when the objects meet. The speed of the object plays an important role in the generation of force of impact. The laws of physics determine that the force of impact increases with the square of the increase in speed.

Based on conventionality in deriving energy, energy sources could be classified as

Conventional ::

coal, oil, hydro, nuclear, etc... sources which can be used up or exhaustible.

(and)

Non - conventional ::

solar, wind, tidal, geothermal, biogas, etc... sources which are not exhausted.

Among the given options, Geothermal energy is the alternative energy source among all the choices that are given in the question, that is exhaustible.

The most important polymer present in the nucleus is DNA- the master molecule. It is a polymer of Nucleotides.

Convection is the mode of heat transfer which involves bulk motion of a fluid to transfer heat. Energy transfer by convection is primarily restricted to fluids. Fluids can be both liquids and gases.

"The moon smiled at me" is the example of personification in the given options.

Personification is a technique in which we give objects human traits like emotions, gestures, speech,... by using metaphor. 

Here moon is an object which cannot smile but using metaphor sense, we gave that sense to it.