If you are interested in UG level Modern Physics i.e., Quantum Mechanics then going for the course work by HC Verma sir will be the most helpful for you. Sir have provided very good lecture with demonstration and the best thing is that the entire course is available for free online, on youtube.

SO you can search HCV Quantum Mechanics on youtube and you will get the videos or you can follow the link below:

https://www.youtube.com/watch?v=cgpnjAYMEOg&list=PLvyl1YgaAepKCqx3e8MJkozbVdYvmN7gw

I hope this helps. Wish you a great day!