Which country shares LONGEST border with India?

India shares the longest border with Bangladesh. Indo bangladesh border spans five of Indian state namely WestBengal, Assam, Meghalaya, Tripura. Mezoram and stretches for 4096.70km. Indo Chinese border stretches for around 4000 km.

What are official names of India?

India and Bharat.

Reference : Constitution of India, article 1
1. Name and territory of the Union.-(1) India, that is Bharat, shall be a Union of States.
_3[(2) The States and the territories thereof shall be as specified in the First Schedule.]
(3) The territory of India shall comprise-
(a) the territories of the States;
_4[(b) the Union territories specified in the First Schedule; and]
(c) such other territories as may be acquired.

Where from the text “Satyameva Jayate” (सत्यमेव जयते, “Truth Alone Triumphs”) inscribed in Devanagari script at the base of the national emblem taken?

Mundaka Upnishad, associated with Atharveda.