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### Course: Class 10 Physics (India)>Unit 1

Lesson 4: Spherical mirrors image formation

# Convex & concave mirror ray diagrams

Let's explore the ray tracing technique to figure out the properties of images when things are kept in front of a concave or a convex mirror. Created by Mahesh Shenoy.

## Want to join the conversation?

• According to what I learned, in the first case of concave mirrors, when the object is placed beyond C (at infinity), isn't the image formed at F (focus) not between F and C (Focus and Centre of curvature)??
Or does it slightly differ, so it can be at F or even between F and C??
• Hey there,
According to my understanding,
the image can be formed at F as well as between F and C,
usually, rays emerging from the object at infinity are considered as parallel to each other making them focus at F check out the previous video
In some cases it is not parallel therefore, formed between F and C
also at around it is 2C or between C and 2C
• What will happen if the object is at pole?
(1 vote)
• pole is the center of the spherical mirror so physically its not possible to put the object there
• is it necessary to take the same rays which are taught ....or can we take different rays for the image formation?/<except the parallel one>
(1 vote)
• Yes, you can draw different rays of light when creating the ray diagram. For example, you can draw a ray of light parallel to the principal axis which reflects off the mirror and passes through the principal focus (like in this video). But also, you can draw a ray of light that passes through the principal focus (on its way to the mirror) and when it bounces off the mirror, it will travel parallel to the principal axis. And then you can draw the ray diagram from there. Although it's it's a bit more complicated for drawing convex mirror ray diagrams, it still works. Hope this helps!
• just started doing 10th physics, 3ish days of goodness
• I think when we keep the object at F we actually putting it on 0 so it becomes infinity and the right hand side is for positive value and hence they are growing as we go right. And the left hand side is for negative values and hence they create a virtual image in the opposite plane.
• Why does the convex mirror have two ray diagrams?
(1 vote)
• Convex mirror has two ray diagrams because its principal focus and the centre of curvature lies behind its reflecting surface. Therefore, not more than two positions of the object can be obtained in relation to these points unlike concave mirrors where more than two ray diagrams are constructed to find out the position of the image for different relative positions of the object.
• for drawing ray diagrams, how do we know where the 2 light rays from the object are drawn from? ex : one light ray passes through focus and another through centre of curvature.
• It's not necessary but making the ray diagrams this way is much easy