Provided you use wire that is rated for 20 amps.
four
7 on a 15 amp circuit and 9 on a 20 amp circuit.
80% of the rated circuit. 10 amp circuit is 8 amps, 20 amp circuit is 16 amps, etc.
If there is nothing else on the circuit then you could easily install 15. If there are outlets on the same circuit then try and keep the total of outlets and lights to a maximum of 15. But in reality the number of devices depends on how many amps each device pulls. Add up the amperage of the recessed lights you are going to install and then add any outlets and what may be plugged into them to get the number you can install. A 100 watt light bulb will draw about 1 amp. So you can easily have 15 on a 20 amp circuit.
A dedicated 20 Amp circuit wired with 12/2 wiring an a 20 amp breaker.
No more than 13 maximum on a 20 amp circuit.
You can safely put 48 regular (incandescent) 40 watt lights on a 20 amp circuit. If at some future date you might place higher wattage lights in the circuit, you will want to limit the number of lights to 20.
The voltage needs to be known to give an answer to this question.
four
A 15a circuit can supply approximately 1650 watts, so 1650/65=25. I would stop at 20.
7 on a 15 amp circuit and 9 on a 20 amp circuit.
A 32 amp fixture can not be fed from a 20 amp breaker as the breaker will trip every time.
80% of the rated circuit. 10 amp circuit is 8 amps, 20 amp circuit is 16 amps, etc.
If there is nothing else on the circuit then you could easily install 15. If there are outlets on the same circuit then try and keep the total of outlets and lights to a maximum of 15. But in reality the number of devices depends on how many amps each device pulls. Add up the amperage of the recessed lights you are going to install and then add any outlets and what may be plugged into them to get the number you can install. A 100 watt light bulb will draw about 1 amp. So you can easily have 15 on a 20 amp circuit.
A dedicated 20 Amp circuit wired with 12/2 wiring an a 20 amp breaker.
Up to 12 on a 20 amp circuit. Up to 9 on a 15 amp circuit. But use common sense. If the circuit will be heavily loaded, as in a home office, then do not install that many.
A 20 amp circuit be used for any device that takes up to 20 amps to make it operate.