Out of all of the 1H series, this class was by far the "easiest", but that does not mean that the class itself is not difficult. The material is rather more straight forward to learn compared to the material of 1BH and the problems are not as difficult as 1AH. You start off the class reviewing some Waves and E&M and then go into optics and sound, with the more conceptually difficult portion being that of diffraction. You then cover some fourier analysis and special relativity. Overall, Professor Ong is a really approachable guy that has really engaging lectures and often brings demos every lecture. If you want to take a class that is a bit more challenging and covers topics that you probably aren't going to see in regular 1C, take this class.