Lenses and Dispersion

Draw the cross-section of a diverging lens.

Using Fig. 5.1, determine the focal length of the lens.

focal length = ______ $\text{cm}$

On Fig. 5.1, draw a vertical arrow of height $2.1\ \text{cm}$ that is $3.0\ \text{cm}$ from the centre of the lens and label the arrow O. The arrow is the object.

On Fig. 5.1, draw two rays from the tip of the object arrow to find the tip of the image.

Draw another arrow to show the image.

Using the image marked on Fig. 5.1 in (b)(iii), determine the linear magnification produced.

magnification = ______

Explain whether the image of the object is real or virtual.

Describe where the display must be positioned relative to the focal length of the lens for the lens to act as a magnifying glass for the image on the display.

Explain how a virtual image is formed.

On Fig. 6.3, draw a ray diagram to show the formation of the virtual image I.

Determine the focal length of the lens.

focal length = ______ $\text{cm}$

indicate the shape of the lens by drawing the outline of the lens around dashed line P

draw the path taken by each ray of light after it passes through the lens.

Fig. 8.2 is a simplified diagram of a short-sighted eye. Light from a distant object strikes the eye lens and enters the eye.

On Fig. 8.2, continue the three rays in the eye until they reach the back of the eye.

State how the image of a distant object detected by a normal eye differs from the image detected by the short-sighted eye.

Explain how a diverging lens corrects the sight of a short-sighted eye viewing a distant object.

Fig. 8.3 is a full-scale diagram drawn on a grid, on which the dashed line L represents the lens and the arrow O the object.

By drawing on Fig. 8.3, find the position of the image I of object O. Draw image I and label it I.

Explain whether the image produced is real or virtual.

On the grid in Fig. 8.3, write an E in a position from which an eye can see the image.

Determine the linear magnification produced.

linear magnification = ______

State the name of the type of lens shown in Fig. 5.1.

______

Describe what happens to the ray of light R:

• as it enters the lens ______
• as it leaves the lens. ______

Using all three rays from O, complete Fig. 5.1 to show the image formed.

Underline all of the words in the list that describe the image formed in (c).

inverted upright real virtual

On Fig. 6.1, draw rays from the top of the object to show how the lens forms an image of the object. Mark the image clearly.

The image is magnified. State one other feature of the image.

______

Calculate the linear magnification produced by the lens in this case.

magnification = ______

State the name of one optical device that produces a magnified image as shown by Fig. 6.1.

______

Define the term linear magnification.

Explain what is meant by real image.

Continue this ray until it meets the image.

Using Fig. 4.1, determine the focal length of the lens.

focal length = ______

Draw another two rays from the top of the object to show how the image is formed.

State the name of the eye defect shown in Fig. 5.1.

Explain what causes the image of the near object to appear blurred.

On Fig. 5.2, draw a suitable lens placed in front of the eye and continue the path of the three rays to the back of the eye.

State what type of lens is used.

Define the term focal length.

On Fig. 6.1, mark and label with an F, each of the two focal points (principal foci) of the lens.

The point Y is the tip of the image.

On Fig. 6.1, draw a ray diagram to locate the position of the top of the object. Label this point X.

Using Fig. 6.1, determine the distance of the candle from the centre of the lens.

distance = ______

State the type of lens used.

______

State what is meant by linear magnification.

On Fig. 3.1, complete the path of the ray from the top of the stamp after it passes through the lens.

Use your drawing to determine the focal length of the lens.

______

On Fig. 3.1, draw two additional rays from the top of the stamp to show how the image is formed.

less than $1.0\text{ cm}$,

more than $1.0\text{ cm}$.

On Fig. 6.1, draw the paths of the two rays after they pass through the lens.

Explain how your ray diagram shows that the image is more than $11\text{ cm}$ from the lens.

Underline three of the following words which describe the image.

diminished      inverted      magnified      real      upright      virtual