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7/27/2019 Latihan Light f1

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1. Figure 2 show a pinhole camera for an experiment.

Figure 2

a. State two characteristics of image formed in the pinhole camera. [ 2 marks ]

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b. What will be if the pinhole is become bigger? [ 2 marks ]

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c. How the image become sharper and bright but without any changes to the apparatus? [ 2 marks ]

_____________________________________________________________________________________ d. Make a conclusion. [ 2 marks ]

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2. Figure 3 show a red light is beam to a white screen with red filter in a dark room.

Figure 3

a. What will show on white screen? [ 1 mark ]

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b. If the red filter changes to green filter, what will happen? [ 1 mark ]

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c. If red light is change to white light, what will change? [ 1 mark ]

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d. Explain your answer in 3 (c). [ 2 marks ] _____________________________________________________________________________________

e. Explain what pigments are. [ 3 marks ]

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CHAPTER 1 : Scientific Investigation

1. Diagram 2 shows the arrangement of apparatus to studt the relationship between the

Length of the thread and the duration of the swing of the pendulum.


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(a) What are the variables involved in this experiment?

(i) Variable that is constant.

Number of swings

(ii) Variable that is manipulated.

Length of thread(iii) Variable that responds.

Time taken for apendulum swing.

(b) What is the relationship between the length of the thread and the duration of the swing of the pendulum.

The longer the thread, the longer the time taken for a pendulum to swing.

(c) If the height of the pendulum from the surface of the table is increased, predict the time taken for the pendulum to swing.

Time taken by the pendulum to swing is shorter.

(d) State one precautionary step when conducting this experiment.

Carry out the experiment in area of calm air.

2. An experiment is conducted to study the relationship between the force (N) and the extension of a spring.The results are shown in Diagram 3.


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(a) State the variable:

(i) That is manipulated

Force

(ii) That responds

Extension of the spring.

(b) What is the relationship between the forces (N)and the extansion of the spring (cm)?

The grater the force applied, the more the spring lengthens.

(c) Study Diagram 3 and fill the data in the table below.

Force/N 1 2 3 4 5

Extansion of the spring/cm 2 4 6 8 10

(d) Predict the extension of the spring if a force of 6 N is applied.

12 cm


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SECTION B

3. Diagram 4 shows a part of the steps in a scientific investigation.

Diagram 4

(a) How can problem be identify?

Always observe phenomena or occurrences that happen in the surroundings.

(b) What is variable

A condition or factor which can be changed in a scientific investigation.

(c) State three variables in a scientific investigations

Variables that are kept constant, manipulated and responds.

(d) What should be done if the hypothesis made is not accepted by the experiment?

A new hypothesis is made.

(e) Identify step x in the scientific investigation.

Plan the investigation.

Identifying a problem Identifying the variables Making a hypothesis Cotrollingthe variables

x


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CHAPTER 7: Light, Colour and Sight

SECTION A

1. Diagram 1.1 shows a part of the light rays on a plane mirror.

(a) Complete Diagram 1.1 by drawing the light rays reaching the observers eye.

(b) What is the relationship between distances X and Y?

X and Y are same distance

(c) State two characteristics of the image formed.

Virtual and upright

(d) In Diagram 1.2,draw the image formed on the plane mirror.Then,state the characteristic

of that image.

Characteristic of image : Inversed laterally


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2. Diagram 2.1 shows an object placed in front of a pinhole camera.

(a) In Diagram 2.1,draw a ray diagram to show the image formed on the screen.

(b) State two characteristics of the image formed.

Real and inverted

(c) What is the effect to the image if

i. The size of the pinhole is enlarged?

More bright but blur.

ii. A convex lens is placed between the object and the pinhole?

The image will be more sharper.

iii. The pinhole camera is moved towards the object?

The image will be more bigger.

(d) Two more pinholes are punched in the camera as shown in Diagram 2.2.Draw and

label the image formed.

3. Diagram 3 shows a 0.7cm high object placed in front of a convex lens.


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(a) Complete the ray diagram to show the formation of an image in Diagram 3.

(b) What is the height of the image formed?

0.7 cm

(c) State two characteristics of the image formed.

Real and inverted.

(d) What optical instrument possesses the object distance of 2F?

Photocopy machine

(e) Why cant the location of the image be determined if the object is less than the

focal length of the lens,F?

The image is virtual.

4. Diagram 4 shows an experiment carried out to determine the focal length of

different convex lens.


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(a) Measure the focal length of the convex lenses in Diagram 4 and write down their

focal length in Table 4.

(b) What is the inference that can be made for this experiment?

The thicker the thickness of the convex lens,the shorter the focal length.

(c) State the variables involved in this experiment.

i. Manipulated : The thickness of convex lens

ii. Respond : The focal length

iii. Constant : Light ray from distant object

(d) State the hypothesis for this experiment.

When the thickness of convex lens increases,The focal length will be decreases.

5. Diagram 5.1 and Diagram 5.2 show the experiment that is carried out to study the

image formed by a pinhole camera.

Thickness of the convex lens Focal length (cm)

Thin 3.6 (0.1)

Thick 2.4 (0.1)


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(a) Draw the light rays in Diagram 5.1 and Diagram 5.2 to show the formation of image.

(b) Measure the size of the image formed in Diagram 5.1 and Diagram 5.2.

i. Size of image in Diagram 5.1 : 0.4 (0.1 cm)

ii. Size of image in Diagram 5.2 : 0.5 (0.1 cm)

(c) State the variables involved in this experiment.

i. Manipulated : Distant of object

ii. Respond : Size of image formed

iii. Constant : Size of the object

(d) What is the hypothesis that can be made in this experiment?

When the distance of the object from the pinhole camera decreases,the size of image

will increases.

(e) State two characteristics of the image formed in this experiment.

Real and inverted.

(f) Predict the size of the image formed if the object is placed 15 cm from the pinhole.

Less than 0.4 cm

SECTION B

6. Diagram 6.1 shows the arrangement of apparatus used to study light dispersion.


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(a) i. What happens to the white lights at the border of the prism?

Refracted

ii. Give a reason for your answer in 6(a)(i) It is because the white light are refracted from one medium to another with

different densities or angles.

(b) What is the colour of the light formed at P and Q on the white cardboard?

P : Red Q : Violet

(c) Complete the boxes below to show the sequence of colours formed in the spectrum.

P(Red),Orange,Yellow,Green,Blue,Indigo,Q(Violet).

(d) A similar prism is palced in the position as shown in Diagram 6.2.

i. What can be observed on the white cardboard?

White light.

ii. State one natural phenomena in which a spectrum can be seen.

Formation of rainbow.


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X : Iris Y : Retina

(c) What is the function of X in the camera?

Controls the size of aperture and amount of light that enters to the camera.

(d) How can a sharp image be focused in a camera?

The lens focuses the image of an object onto the film.The lens is adjusted by the

focus adjuster either towards or away from the film to obtain a sharp image.

8. Diagram 8 shows the formation of a rainbow after an evening rain.

(a) How is a rainbow formed?

- Sunlight shines on the raindrop.

- A part of the light is reflected off the outer surface of the raindrop.

- A part of the light is refracted at the different angles in the raindrop.

- The light is split into its colour constituents through dispersion.

- The colour constituents are reflacted off the far inner surface of the raindrop.

- Light refraction occurs again as it exits the raindrop.A rainbow is formed.


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(b) What is the role of the raindrops?

Act as a prism.

(c) State two processes that occurred to the sunlight at X? Dispersion and refracted.

(d) What process occurs to the sunlight at Y?

Reflected

9. Diagram 9 shows the arrangement of apparatus to study the addition of coloured light.

(a) What colours are formed in the regions of X,Y and Z?

X : Red Y : Magenta Z : Blue

(b) i. Of the colours formed on the screen,which is the secondary colour?

Magenta.

ii. Give a reason for your answer in 9(b)(i).

Magenta can only be produced from addition of two primary colours,blue and red.

(c) What coloured light is formed in region X if a yellow filter is placed in front of the

red filter in torch P?

Red.


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(d) What coloured light is formed in region Z if a green filter is placed in front of the

blue filter in torch Q?

No colour formed.

(e) If a piece of cyan cloth is placed under the light rays in region Y,what colour will the

cloth appear as?

Blue.

SECTION C

1. Study the following statement.

(a) Suggest one hypothesis to investigate the above statement.

Hypothesis : The thicker a lens,the shorter its focal length.

(b) i. Aim : To estimate the focal length of a convex lens and relate it to the thickness of

the lens.

ii. Variable that :

- Constant : Object distance

- Manipulated : Thickness of the lens

- Respond : Focal length

iii. List of apparatus and materials : Metre ruler,screen,convex lenses with vary

thickness,lens holder.

The spectacles of old people have shorter focal length than those of a student who is

long-sighted.This is because the lenses in their spectacles have a different thickness.


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iv. Procedure :

- The arrangement of apparatus is set up as shown in the diagram below,facing an

object outside the window.

- The screen is adjusted until a sharp image is formed on it.

- The focal length is measured with a metre ruler.

- The experiment is repeated using lenses of different thickness.

v. Tabulation of data :

vi Conclusion : A thick convex lens has a short focal length while a thin convex lens has

a long focal length.

Thickness of the lens Focal length, f/cm

Thin

Thick


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mirror.

- The second mirror reflects the light rays to the eyes of the student.

12. (a) Compare the images formed by a concave lens and a magnifying glass.

- The images formed by a concave lens and a magnifying glass are virtual

and upright. - A magnifying glass forms a bigger image than the object.

(b) Diagram 12 shows the colours that appear in the screen when white light is passed

through the coloured filters.

i. Identify the problem :

- A red filter only allows green light to pass through it.

- A green filter only allows green light to pass through it.

ii. Identify two common characteristics :

- Red and green coloured filters only allow their own colours to pass

through them.

- Other colours are absorbed by red and green coloured filters.

iii. Initial concept :

Red and green coloured filters only allow their own colours to pass through

them but absorb other colours showing that they are primary colours.


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iv. Example : Blue

Non-example : Yellow,cyan,magenta

v. Actual concept :

Primary filters only allow their own colours to pass through them but absorbedother colours.

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