Questions

Optical illusion is what that refers to persistence of vision with a principle that multiple images blend into a single image in human mind and what is showed in cinema.

Hence, Persistence of vision is the principle behind cinema.

Lima is the capital of Peru

This difference proves that the earth is flattened at the poles and is thus, not a perfect sphere. The shape is reffered to as "geoid"

You have to consider three things.

1. First, are the bonds polar?

Look at differences in electronegativity and if  it is >0.5, bonds are polar.

2. Second, does the molecule have unshared electron pairs?

If so, they generally lead to a polar molecule.

3. Third, is the molecule symmetric?

If so, then although the bonds may be polar, the symmetry cancels out the individual bond polarity and the molecule is non polar.

CF4 follows all the rules above and has a symmetric distribution of charge, making it nonpolar. The others all have asymmetric charge distributions.

Hence, CF4 represents a Non-polar molecule.