Lenses

The ray diagram shows how an image is formed by a converging lens:

What is it’s focal length ?

• 8 cm

• 10 cm

• 18 cm

• 24 cm

A thin converging lens is used to produce, on a screen, a focused image of a candle:

The screen and the lens are moved back and forth and various focused images are produced on the screen.

Which statement is always true?

• The image is at the principal focus (focal point) of the lens.

• The image is bigger than the object.

• The image is closer to the lens than the object is.

• The image is inverted.

A parallel beam of light falls on a converging lens. Which diagram shows what happens to the beam of light?

• A

• B

• C

• D

Two thin converging lenses X and Y are used as shown to give a focused image of an illuminated slit. The rays shown are parallel between X and Y:

What are the correct values for the focal lengths of X and of Y?

• A

• B

• C

• D

In the diagram, the distance OP is the focal length of the lens. Through which point will the ray shown pass, after refraction by the lens?

• A

• B

• C

• D

The diagram shows the path of a ray of light passing through a principal focus F of a lens. Which broken line shows the direction of the ray after it leaves the lens?

• A

• B

• C

• D

An object O is placed in front of a converging lens of focal length f. At which point will the top of the image be seen?

• A

• B

• C

• D

An object is placed in front of a converging lens. The lens has a focal length f. The lens produces a real, enlarged image of the object. In which labelled position is the object placed?

• A

• B

• C

• D

A student draws a diagram representing three rays of light from point P passing through a converging lens. Each point labelled F is a principal focus of the lens:

Which of the rays has the student drawn correctly?

• Ray X and ray Y

• ray X and ray Z

• ray Y only

• ray Z only

The diagram shows a converging lens forming an image of an object:

Which statement about the image is correct?

• It is real and can be seen by an eye at X.

• It is real and can be seen by an eye at Y.

• It is virtual and can be seen by an eye at X.

• It is virtual and can be seen by an eye at Y.