### Punjab Board > 9th > Physics (Total Videos: 48)

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##### Chapter 9: Optics (7 videos)
###### 9.1: Laws of refraction
1. Verify laws of refraction of light by using glass slab
###### 9.2: Refractive index of water
1. Find refractive index of water by concave mirror
###### 9.4: Focal length of lens
1. Find focal length of convex lens by parallax method