At what distance from a converging lens of focal length 12cm must an object be placed in order that an image of magnification 1 will be produced?

Name the two types of spherical mirrors. What type of mirror is represented by the:

1. Back side of a shining steel spoon?
2. Front side of a shining steel spoon?

How does the light have to enter the glass:

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

Draw a ray diagram to show the path of the reflected ray corresponding to an incident ray of light parallel to the principal axis of a convex mirror and show the angle of incidence and angle of reflection on it.

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?

A large concave mirror has a radius of curvature of 1.5m. A person stands 10m in front of the mirror. Where is the person’s image?

With the help of a ray diagram explain why a concave lens diverges the rays of a parallel beam of light.

An object of height 2.5cm is placed at a distance of 15cm from the optical centre ‘O' of a convex lens of focal length 10cm. Draw a ray diagram to find the position and size of the image formed. Mark optical centre ‘O', principal focus F and height of the image on the diagram.

Why does a ray of light passing through the centre of curvature of a concave mirror gets reflected along same path after reflection?