Lens

The focal length is

• the distance from the light source to the image.

• the distance from the object to the centre of the lens.

• the distance from the image to the centre of the lens.

• the distance from the focal point to the centre of the lens.

Which of the following are true?

1. The principal focus of a converging lens is real.

2. The principal focus of a diverging lens is virtual.

3. The principal focus of a lens is always along the principal axis.

• 1 and 2

• 2 and 3

• 1 and 3

• 1, 2 and 3

Which of the following is true?

• The image distance obtained from a far away object is the focal length of the convex lens.

• The images obtained from a convex lens always lie on the focal point.

• The images obtained by a convex lens are always real.

• The images obtained by a convex lens are always inverted.

An object O is placed at the position shown. What are the characteristics of the image produced?

• real, inverted and diminished

• real, inverted and enlarged

• virtual, inverted and diminished

• virtual, upright and enlarged

An object O is placed at the position shown. What are the characteristics of the image produced?

• real, inverted and diminished

• real, inverted and enlarged

• virtual, upright and enlarged

• no image formed