Questions

Optical fiber works on the principle of total internal reflection.

The Total Internal Reflection is the phenomenon in which the complete reflection of a light ray reaching an interface with a less dense medium when the angle of incidence exceeds the critical angle.

Polyglot - A person who knows or speaks many languages.

Linguist - A person who speaks  foreign languages.

‘Were’ needs to be replaced with ‘was’ to make the sentence grammatically correct. This is because, ‘If the subjects are joined by as well as, with, along with, together with, and not, in addition to, but, besides, except, rather than, accompanied by, like, unlike, no less than, nothing but, led by, headed by, guided by, controlled by,governed by,etc.. Then the verb will agree with the first subject. Thus, the correct formation would be, ‘The teacher as well as his wife was invited’.

MEDDLE means interfere in something that is no one’s concern.