What is the position of image when an object is placed at a distance of 10cm from a convex lens of focal length 10cm?

Draw ray diagrams showing the image formation by a concave lens when an object is placed:Between focus and twice the focal length of the lens.

The boy walks towards the mirror at a speed of 1m/ s. At what speed does his image approach him?

What type of lens is shown in the diagram on the right? What will happen to the parallel rays of light? Show by completing the ray diagram.

A student focuses the image of a well illuminated distant object on a screen using a convex lens. After that he gradually moves the object towards the lens and each time focuses its image on the screen by adjusting the lens.

1. In which direction-towards the screen or away from the screen, does he move the lens?
2. What happens to the size of the image-does it decrease or increase?
3. What happens to the image on the screen when he moves the object very close to the lens?

The following table gives the refractive indices of a few media,

	1	2	3	4	5
Medium:	Water	Crown glass	Rock salt	Ruby	Diamond
Refractive index:	1.33	1.52	1.54	1.71	2.42

Use this table to give an example of:

1. A medium pair so that light speeds up when it goes from one of these medium to another.
2. A medium pair so that light slows down when it goes from one of these medium to another.

Draw ray diagrams showing the image formation by a convex mirror when an object is placed:
At finite distance from the mirror.

How does the light have to enter the glass:

1. To produce a large amount of bending?
2. For no refraction to happen?

What is the position of the image when an object is placed at a distance of 20cm from a concave mirror of focal length 20cm?

Draw ray diagrams showing the image formation by a convex lens when an object is placed:
At the focus of the lens.