Ray diagram construction for concave mirrors

Presented by

Obina Johnson Okeny

Objectives:

• To show how rays travel in order to form images in a concave mirrors.

• To show and state the nature of images formed.

The paths of three rays are known.

a. Rays traveling parallel to the principal axis

b. Rays passing through the principal focus

c. Rays passing through the centre of curvature

C F P

(a) Rays parallel to the principal axis are reflected and they pass through the principal focus

(b) Rays passing through the principal focus (F) will move parallel to the principal axis after reflection

C F P

(c) Ray passing through the centre of curvature (C) are reflected back along their own paths because they are normal to the mirror

C F P

FC P

I am parallel to the principal axis. Always draw me first

I am the Object

I am reflected parallel to the principal axis

Now let us draw a ray diagram for an object beyond C

FC P

I am parallel to the principal axis. Always draw me first

I am the Object

I am reflected parallel to the principal axis

Now let us draw a ray diagram for an object at C

I am the image. What is my nature?

FC P

I am parallel to the principal axis.

I am the Object

I am reflected parallel to the principal axis

Now the object is between C and F

I am the image now. What is my nature?

FC P

I am the Object

Now let us draw a ray diagram for an object at F

We will meet at infinity to form a

real, inverted magnified image.

FC P

I am the Object

I am reflected parallel to the principal axis

Now let us draw a ray diagram for an object between F and P

I am the image. What is my

nature now?

THANK YOU!

You have been wonderful.obinaokeny@yahoo.com