How many 6'cN LIGHTS CAN BE PUT ON A 15 mp circuit

1440 watts, or 14 100 watt bulbs, plus a 40 watt bulb.
You can use 24 60 watt bulbs.
1440/120=24.

In the home, lighting is not generally considered a continuous load, it is also not usually all on at the same time. You can have 1800 watts on a 15 amp circuit.