7 Convex LensesCan act as a magnifying glassEach lens has its own focal length (the distance from the centre of the lens to the focal point)
8 The greater the curvature of the lens, the shorter the focal length The greater the curvature of the lens, the shorter the focal length. (pg. 217)
9 Lenses have focal points on either side because light shines through either side. The line through the centre of the lens is called the principle axis.Optical centre is where the principle axis meets the lens centre.