Refraction and Diffraction Lessons

​When light hits a boundery (change of medium), some light will reflect but the rest refracts by slowing down, but why…
https://youtu.be/NLmpNM0sgYk?si=_YXVsioc6HZ-rguU

Dry Lab for Optical (wave) Nature of EMR

​https://youtube.com/shorts/b-Joj9d4aBI?si=xCTwnrnR4EbzAvxO

​Now, Consider if the same object were placed in front of a convex lens with a real focal length of 12.3cm.
What would the properties of the image be? (d_i , h_i , etc...)

​Recall from this mirror question that the d_i is negative confirming the virtual nature of the image, and that the focal length would also be negative
(which is always true for diverging mirrors).

​https://www.youtube.com/watch?v=IRBfpBPELmE&list=PL4GeZoa9_FQDK1sTrZP-WdlVu4C2Z1QJt&index=10