However, if the adapter is quite hot, enough that it could hurt your hand after touching it for just a few seconds, this is a potential problem. An adapter that hot is a warning sign that something could be wrong with the adapter or the laptop.
The first thing to check is whether the laptop battery is gaining any charge with the adapter plugged in. If it is, then the issue is most likely with the adapter itself. If the battery is not charging, there could be an issue with the power connection in the laptop as well as the adapter.
Also, check the adapter end that connects to the laptop and the power connection on the laptop for any possible damage, including a bent pin inside the connector or any bend/break marks in the metal jacket of the connector. If you notice any damage, replace the adapter or have the laptop repaired.
If you notice the adapter is very hot, turn off your computer and unplug the power adapter from the wall outlet. Let it cool down completely, then plug it back in to the wall outlet and turn on the laptop. Monitor the temperature of the adapter for a little while and if it becomes very hot again, it is recommended that you take the laptop and power adapter to a computer repair shop and have them check it over. An issue like this is not something you want to ignore, as it could cause serious damage to a laptop or even potentially start a fire.