Headphone impedance on my n5110?

The laptop output (which is a low impedance) is suitable for all normal "low impedance" phones which covers 99% of what you will come across. Most headphones are in the 10 to 50 ohm impedance range.

If you try and use high impedance phones (say 600 ohm or higher) then you will find the audio level too quiet as they need a lot of voltage to drive them.

D_railed , the IDT 92HD87 data sheet can be googled and downloaded. That is the audio chip in the N5110 line. It confirms what Mooly01 said.

Most headphones are in the 10 to 50 ohm impedance range.

In the IDT 92HD87 data sheet, they use a load of 32 ohms when determining the impedance and wattage of the headphone outputs of the chip, so I would think that 32 is a typical number. They use a load of 32 ohms and also 10,000 ohms to determine the signal to noise ratio. In both cases the SNR is 95dB.

The data sheet says "The capless headphone drivers are supplied with +/-2.5V derived from AVDD. Therefore, it is possible
to run the headphone supply from 5V and maintain ~60mW peak output power into 32 ohm
headphones. Headphone performance will degrade if more than one port is driving a 32 ohm load."

The laptop output (which is a low impedance)

According to the data sheet  the headphone outputs of the amp are 0.1 ohm.

Just want to thank Mooly01 for the help...thank you very much!