Question

1. The fluorescent lamp is over the desk.
2. An ant is beneath the table.
3. The cat is under the table.
4. A book is on the table.
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Does #1 mean that the fluorescent lamp is right above the table? If the fluorescent lamp is in the corner and the lamp is not right above the table, do we have to use 'above' as follows?

5. The fulorescent lamp is above the table.

Answer 1

Sentences 1 and 5 read as if the fluorescent lamp is attached to the wall or ceiling and is over or above the desk.
http://homeli.co.uk/wp-content/uploads/2013/12/Ninebyfour-Light-Over-Desk.jpg

If the lamp is a free-standing lamp, it would be ON the desk.
http://cdn.home-designing.com/wp-content/uploads/2012/09/5-Silver-desk-lamp1.jpeg

All the others are correct.