Starter (5 mins): Draw ray diagrams an object is standing in front of a convex mirror. an object is standing 5 cm away from a concave mirror with the radius of 6 cm. an object is standing 2 cm away from a concave mirror with the radius of 6 cm.

P = pole , pa = principal axis F P r pa f P = pole , pa = principal axis C = centre of curvature r = radius of curvature F = Focal point or focus f = focal length f = r / 2

Descarte’s Formula Newton’s Formula and Newton’s Formula (with mirrors)

Descartes’ Formula (with Mirrors) f = focal length di = distance between image and mirror do = distance between object and mirror Note: f is negative if the mirror is convex di is negative if the image is virtual

Example: Find the position and the nature of the image of an object located 40 m in front of a concave mirror with the radius of curvature 64 m.

Magnification Factor m = magnification factor hi = height of the image ho = height of the object Remember: m < 1 if the image is diminished m > 1 if the image is enlarged

Example: An object 7 m high is placed 15 m from a convex mirror of radius 45 m. Find the position, the nature AND the height of the image.

Newton’s Formula (with Mirrors) Si = distance between image and focus So = distance between object and focus Note: Si and So are always positive – which means you can not tell which side of the mirror the image/object is.

Example: An object 7m high is placed 15m from a convex mirror of radius 45m. Find the position and the nature of the image.

Magnification Factor m = magnification factor hi = height of the image ho = height of the object Remember: m < 1 if the image is diminished m > 1 if the image is enlarged

Example: An object 6m high is placed 30m in front of a convex mirror of focal length 40m. Find the position, nature and size of the image formed.

Mirrors Formulae Worksheet Homework Booklet: MIRRORS (five questions) Textbook: Activity 5B