LESSON 5.5 - Use of Lenses in Optic Devices

S M K Pahi Bidang sains dan matematik LESSON 5.5 - use of lenses in optic devices

LESSON 5.5 - Use of Lenses in Optical Devices Introduction Optical Normal Characteristics Uses Ray diagram device adjusment of final iamges Magnifying glass

Microscope

Telescope

Camera

Slide projector

1 S M K Pahi Bidang sains dan matematik LESSON 5.5 - use of lenses in optic devices There are many types of optical devices used lenses A Consist of a concave lens which has lower such as magnifying glass, microscope, telescope, power than the objective lens. camera and slide projector etc. For every types of B Consist of a convex lens which has lower the devices we must learn about the uses of the power than the objective lens. instruments, lens characteristics is used, normal C Consist of a concave lens which has adjustment of the instruments , ray diagrams and the higher power than the objective lens. characteristics of the final image which are formed . D Consist of a convex lens which has higher power than the objective lens. 6 Which of the following is true concerning the operation of a compound microscope? TUTORIAL 5 A The focal length of objective lens greater 1 Which of the following combinations is the than The focal length of characteristics of a magnifying lens ? B Both objective lens and eyepiece has a high power. Focal length/ cm Object distance/ cm C The characteristics of final image are magnified, upright and virtualI A 5 10 B 8 5 7 The characteristics of image is formed by the C 10 5 objective lens of a microscope are D 20 8 A virtual,diminished,upright 2 A convex lens is used as a magnifying glass. B real,magnified,inverted What are the characteristics of the image? C virtual,magnified,inverted D real,magnified,upright A magnified,upright,virtual B magnified,upright,real 8 Which of the following pairs of lens are used to C magnified,inverted,virtual construct a telescope? D magnified,inverted,real A A concave lens of focal length 3 cm and a 3 Choose the most suitable combinations of the concave lens of focal length 120 cm lens that be used to construct a microscope. B A convex lens of focal length 3 cm and a convex lens of focal length 120 cm C A concave lens of focal length 100 cm and first lens Second lens a concave lens of focal length 120 cm D A convex lens of focal length 100 cm and Concave lens of Concave lens of A a convex lens of focal length 120 cm focal length 3 cm focal length 120 cm Convex lens of focal Convex lens of focal B 9 Which of the following statements about the length 3 cm length 120 cm objective lens and eyepiece of a telescope? Concave lens of Concave lens of Power of objective Power of C focal length 3 cm focallength 5cm lens eyepiece Convex lens of focal Convex lens of focal A low high D length 3 cm length 5cm B high low C low low

D high high 4 Which of the following is true about the eyepiece of a microscope?

1 S M K Pahi Bidang sains dan matematik LESSON 5.5 - use of lenses in optic devices 10 Two convex lens of power 2.5D and 20 D 14 How can we modify a telescope to increase the respectively is used in a telescope. What is the linaer magnification and the brightness of the distance between the lens in normal image? adjustment? A reduce the focal length and the diameter A 8.0 cm B 17.5 cm of eyepiece C 22.5 cm D 45.0 cm B increase the focal length and the diameter E 50.0 cm of eyepiece C reduce the focal length and increase the 11 Two convex lens of focal length 100 cm and 5 diameter of objective lens cm respectively is used in a telescope. What is D incraese the focal length and the diameter the linear magnification of the telescope? of objective lens

A 0.05 B 20 15 The characteristics of final image in a telescope C 100 D 105 are E 500 12 A telescope has two convex lens of power 4.0 D A virtual,upright,magnified,located at the and 20.0D respectively. focal point Which of the following is true? B real,inverted,magnified,located at infiniti C virtual ,inverted,magnified,located at infiniti Linear Distance between the lens magnification /cm 16 What are the similarities characteristic between A 5 24.0 microscope and telescope ? B 5 30.0 C 4 30.0 A Both have an eyepiece of long focal D 4 24.0 length E 0.2 16.0 B The final image of the both instruments are magnified,inverted and virtual

C The principal focus of the objective lense 13 The diagram shows the design of a simple is coincident with the principal focus of the astronomical telescope. eyepiece The focal length of the lens P is f and the focal p length of the lens Q is f Q. 17 The characteristics of the image is formed by a camera are

A virtual,upright ,enlarged B real,inverted,diminished C virtual,inverted,diminished D real,upright,enlarged

Which statement is correct? 18 A slide projector has a convex lens of focal length, f. It is used to produce real and enlarged image ,when the slide is placed A fPis shoter than fQ B The power of lens P is higher than lens Q C The image of lens P is real whereas the A less than f image of lens Q is virtual B at f C between f and 2f D The image magnification is the ratio fQ to fP D at 2f

2 S M K Pahi Bidang sains dan matematik LESSON 5.5 - use of lenses in optic devices

22 The diagram shows the arrangement of the 19 The image is formed by a slide projector is lenses in a compound microscope.

A enlarged,real,upright B enlarged,real,inverted C diminished,virtual,upright D diminished,real,inverted

20 Which of the following optical instrument produced real image?

A Telescope B Magnifying glass C Mikroscope D Slide projector

21 A convex lens of focal length 4 cm is used as a magnifying glass. An object is placed in front of the lens. (a) Complete the ray diagaram in the diagram above. (a) Using scale menggunakan 1 cm : 2 cm, (b) State the characteristics of the final image draw a ray diagram to show how the formed. convex lens acts as a magnifying glass ......

......

Telescope Microscope

(b) State the characteristics of the image formed.

......

(c) What happen to the image when a secreen is placed at the behind of the lens? 23 The diagram shows the arrangement of the lenses in a compound microscope. The power ...... of lens A and lens B are 0.5 D and 5D respectively. (d) Determine the power of the magnifying glass.

3 S M K Pahi Bidang sains dan matematik LESSON 5.5 - use of lenses in optic devices (g) How can we modify a telescope to increase the linaer magnification and the brightness of the image?

......

……………………………………………………….

24 A student wishes to construct a telescope using (a) Why do the light rays PQ and RS are two convex lenses to observe the eclipse of the parallel? moon. Besides the lens of power 5 D, the student is provided with an additional of two convex lenses of power 2 D and 10 D...... (b) State the focal length of (a) State the possible combinations of any (i) lens A two lenses that can be used to construct the telescope......

(ii) lens B ………………………………………………......

...... (c) What is the distance between lens A and ……………………………………………………… lens B? (b) Calculate the final image magnification of the telescope for each combination in (a) used at normal adjustment.

(d) What is the linear magnification of the

telescope?

(e) In the diagram above , complete the ray diagram of the telescope. (c) Choose the best combination from (b) to observe the eclipse of the moon clearly. Give one reason.

………………………………………………... (f) State the characteristics of the final image formed. ………………………………………………..

......

……………………………………………….. 25 The figure shows the lens and mirror arrangement for a slide projector.

4 S M K Pahi Bidang sains dan matematik LESSON 5.5 - use of lenses in optic devices

(a) What is the function of (i) concave mirror

...... (ii) condenser lens

...... (b) State two normal adjustment should be done while using the slide projector.

......

………………………………………………… (c) State the characteristics of the final image formed..

...... (d) A slide of area 4 cm2 is placed in front of the convex lens at a distance formed a sharp image on the screen. The distance between the slaid and the screen is 250 mm. Calculate

(i) the linear magnification of the image.

(ii) the area of the image on the screen

(iii) the focal length of the convex lens.