Upper Secondary: Thin Lenses

Which is the focal point?

• A

• B

• C

• D

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 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.

What are the characteristics of the image produced?

• virtual

• enlarged

• inverted

• upright

• real

What are the characteristics of the image produced?

• real, inverted and diminished

• real, inverted and enlarged

• virtual, upright and enlarged

• no image formed

What are the characteristics of the image produced?

(a)  

Where is the position of the converging lens?

• A

• B

• C

• D

A camera uses a converging lens to produce an image on the film. If the focal length of the lens is 10 cm, where should an object be placed from the camera for photo taking?

• 10 cm

• 15 cm

• 20 cm

• 100 cm

A photocopy machine uses a converging lens to focus images for printing on papers. If the focal length of the lens is 6 cm, what is the distance from the original copy to the lens during photocopying?

• 2 cm

• 6 cm

• 10 cm

• 12 cm

A converging lens is used to magnify a virtual image to four times its original size. Given that the focal length of the converging lens is 20 cm, what is the object distance?

• 5 cm

• 10 cm

• 15 cm

• 25 cm