Cameras

Learn it by playing

Answer these questions to earn energy, then fish and explore. No account needed.

For teachers: ready-to-use lesson slides, revision notes, diagrams for Cameras (KS3 Science, Physics) — use them in your lesson, or run the topic as an interactive class activity your students play as a live game.

Lesson notes

Pinhole Camera

A **pinhole camera** is a simple device that forms an image using a small hole.
It consists of a box with a **small hole** at one end and a **translucent screen** (e.g., tracing paper) at the other.
**Translucent** means allows some light to pass through, but not clear.
Light rays from the object travel in straight lines through the pinhole.
The image formed is **inverted** (upside down) because rays from the top and bottom cross at the pinhole.
The image is formed on the screen and can be seen from outside.

Modern Camera

A modern camera uses a **convex lens** instead of a pinhole.
The convex lens **refracts** (bends) light rays to bring them to a **focus**.
The camera has a **light-sensitive sensor** (like the retina in the human eye).
The sensor captures the focused image and converts it into an electronic signal.
Even small phone cameras contain a lens and a sensor.

Comparison with the Human Eye

Both the human eye and a camera contain a **convex lens** to focus light.
The eye's **retina** is equivalent to the camera's **sensor**.
Both produce an inverted image on the retina/sensor, but the brain corrects it for the eye.

Key Terms

**Inverted**: upside down relative to the object.
**Translucent**: allows light to pass through diffusely.
**Refraction**: bending of light when it passes from one medium to another.
**Convex lens**: a lens that bulges outward and converges light rays to a point.

Refraction of light through a convex lens (simplified).

Slides

Step through every slide for this topic — plus flashcards and revision notes — with a free account.

Practice questions

Free preview — 8 of 40 questions. Sign up to see them all.

1.What does it mean if a material is translucent?
Easy
- AIt allows all light to pass through.
- BIt allows some light to pass through.
- CIt allows no light to pass through.
- DIt reflects all light.
2.What does 'inverted' mean when describing an image in a pinhole camera?
Easy
- AThe image is smaller than the object.
- BThe image is upside down.
- CThe image is the same size as the object.
- DThe image is larger than the object.
3.Which part of a modern camera is equivalent to the retina in the human eye?
Easy
- ALens
- BSensor
- CScreen
- DAperture
4.Which of the following statements is true?
Easy
- AA pinhole camera contains a convex lens.
- BThe human eye contains a convex lens, but a camera does not.
- CBoth the human eye and a camera contain a convex lens.
- DNeither the human eye nor a camera contains a convex lens.
5.What is the screen of a pinhole camera typically made of?
Easy
- ACardboard
- BTracing paper
- CGlass
- DMetal
6.A student makes a pinhole camera with a larger hole. What effect does this have on the image?
Medium
- AThe image becomes sharper.
- BThe image becomes brighter but blurrier.
- CThe image becomes dimmer but sharper.
- DThe image becomes inverted.
7.In a pinhole camera, why is the image inverted?
Medium
- ABecause the screen is curved.
- BBecause light rays travel in straight lines and cross at the pinhole.
- CBecause the box is light-tight.
- DBecause the pinhole is too small.
8.Which of the following is NOT a component of a modern camera?
Medium
- AConvex lens
- BSensor
- CRetina
- DAperture

More questions

9.What is the function of the convex lens in a camera?
Medium
- ATo spread light out
- BTo refract light to a focus
- CTo block unwanted light
- DTo invert the image
10.In a pinhole camera, if the object is moved closer to the pinhole, what happens to the image?
Hard
- AIt becomes smaller and upright.
- BIt becomes larger and inverted.
- CIt becomes larger and upright.
- DIt becomes smaller and inverted.
11.A student claims that a pinhole camera can form an image without a lens. Is this correct?
Hard
- AYes, because light travels in straight lines through a small hole.
- BNo, because a lens is needed to focus light.
- CYes, but only if the hole is very large.
- DNo, because the image would be too dim.
12.What is the main advantage of a modern camera over a pinhole camera?
Hard
- AIt produces a brighter image.
- BIt produces an upright image.
- CIt does not require a screen.
- DIt can produce a focused image with more light.
13.A student makes a pinhole camera with a screen made of tracing paper. Which property of tracing paper makes it suitable for use as a screen?
Medium
- AIt is opaque and reflects light.
- BIt is translucent and allows some light to pass through.
- CIt is transparent and allows all light to pass through.
- DIt is shiny and produces a clear reflection.
14.In a pinhole camera, light rays from the top of the object travel in a straight line through the pinhole. Where do they hit the screen?
Medium
- AAt the top of the screen.
- BAt the bottom of the screen.
- CAt the centre of the screen.
- DThey do not reach the screen.
15.A student makes a pinhole camera using a box of length 20 cm. The object is 40 cm tall and placed 60 cm from the pinhole. What is the height of the image on the screen?
Hard
- A10 cm
- B13.3 cm
- C20 cm
- D30 cm
16.In a modern camera, the lens focuses light onto the sensor. If the lens is replaced by one with a shorter focal length, what happens to the image?
Hard
- AThe image becomes larger and dimmer.
- BThe image becomes smaller and brighter.
- CThe image becomes larger and brighter.
- DThe image becomes smaller and dimmer.
17.Which of the following correctly compares the human eye and a modern camera?
Medium
- AThe eye has a lens; the camera has a pinhole.
- BThe eye has a retina; the camera has a sensor.
- CThe eye has a pupil; the camera has a lens.
- DThe eye has a cornea; the camera has a screen.
18.What is the main purpose of the convex lens in a camera?
Easy
- ATo spread light out.
- BTo refract light to a focus.
- CTo reflect light onto the sensor.
- DTo block out unwanted light.
19.A pinhole camera has a pinhole of diameter 0.5 mm. If the pinhole is enlarged to 1.0 mm, what effect does this have on the image?
Hard
- AThe image becomes sharper and brighter.
- BThe image becomes blurrier and brighter.
- CThe image becomes sharper and dimmer.
- DThe image becomes blurrier and dimmer.
20.What does the term 'inverted' mean when describing an image in a pinhole camera?
Easy
- AThe image is smaller than the object.
- BThe image is upside down.
- CThe image is larger than the object.
- DThe image is the same size as the object.
21.Which of the following statements about a pinhole camera is true?
Medium
- AIt uses a convex lens to form an image.
- BThe image is always upright.
- CThe image is formed on a translucent screen.
- DThe image is formed inside the box without a screen.
22.In a modern camera, the aperture (opening) is reduced in size. What is the effect on the depth of field (the range of distances that appear in focus)?
Hard
- ADepth of field decreases.
- BDepth of field increases.
- CDepth of field remains the same.
- DDepth of field becomes zero.
23.A student points a pinhole camera at a bright object. The image on the screen is blurry. Which change would make the image sharper?
Medium
- AMaking the pinhole larger.
- BMaking the pinhole smaller.
- CMoving the screen closer to the pinhole.
- DUsing a thicker screen.
24.What type of material is the screen of a pinhole camera typically made from?
Easy
- ACardboard
- BTracing paper
- CAluminium foil
- DGlass
25.A student constructs a pinhole camera using a cardboard box and tracing paper. They notice the image is dim. Which modification would most effectively brighten the image while keeping it reasonably sharp?
Medium
- AEnlarge the pinhole slightly
- BUse a larger box
- CReplace the tracing paper with a thicker paper
- DMove the object closer to the pinhole
26.In a pinhole camera experiment, a student places an object 30 cm from the pinhole and obtains an image height of 2 cm on a screen 15 cm behind the pinhole. What is the height of the object?
Hard
- A4 cm
- B1 cm
- C2 cm
- D8 cm
27.A student makes a pinhole camera and uses it to view a candle flame. The image on the screen is inverted. Which statement correctly explains why the image is inverted?
Medium
- ALight rays from the top of the flame travel straight through the pinhole and hit the bottom of the screen
- BThe convex lens inside the camera refracts the light upside down
- CThe screen is placed at an angle
- DLight rays reflect off the inside of the box
28.Which component in a modern camera is sensitive to light and converts the image into an electrical signal?
Easy
- ASensor
- BLens
- CAperture
- DRetina
29.A student investigates how the size of the pinhole affects the image. They use pinholes of diameters 0.2 mm, 0.5 mm, and 1.0 mm. Which of the following correctly describes the results?
Medium
- AThe 0.2 mm pinhole gives the sharpest but dimmest image
- BThe 1.0 mm pinhole gives the sharpest and brightest image
- CThe 0.5 mm pinhole gives the brightest image
- DAll pinholes produce images of the same brightness
30.A pinhole camera is used to photograph a tree. The distance from the tree to the camera is 5 m, and the camera length is 25 cm. The image of the tree on the screen is 4 cm tall. What is the actual height of the tree?
Hard
- A80 cm
- B8 m
- C0.8 m
- D80 m
31.What property must the screen material of a pinhole camera have to allow an image to be seen from the outside?
Easy
- ATranslucent
- BTransparent
- COpaque
- DReflective
32.A student wants to make the image in a pinhole camera larger without changing the camera. Which action should they take?
Medium
- AMove the object closer to the pinhole
- BMove the object farther from the pinhole
- CMake the pinhole smaller
- DUse a brighter object
33.In a pinhole camera, if the distance from the pinhole to the screen is doubled, what happens to the size of the image of a distant object?
Hard
- AIt doubles
- BIt halves
- CIt stays the same
- DIt quadruples
34.Which part of the human eye is equivalent to the sensor in a modern camera?
Easy
- ARetina
- BLens
- CPupil
- DCornea
35.A student sets up a pinhole camera with a screen made of tracing paper. They observe that the image is faint. Which change would most improve the brightness of the image?
Medium
- AUse a larger pinhole
- BUse a smaller pinhole
- CMove the screen closer to the pinhole
- DPaint the inside of the box black
36.A pinhole camera has a length of 20 cm. An object 10 cm tall is placed 40 cm from the pinhole. What is the height of the image on the screen?
Hard
- A5 cm
- B2 cm
- C20 cm
- D0.5 cm
37.A student uses a pinhole camera to view a tall building. The building is 50 m away from the camera. The camera is 30 cm long. The image of the building on the screen is 5 cm tall. What is the actual height of the building?
Medium
- A83.3 m
- B300 m
- C8.33 m
- D30 m
38.A pinhole camera has a length of 25 cm. An object 20 cm tall is placed 100 cm from the pinhole. What is the height of the image on the screen?
Hard
- A5 cm
- B8 cm
- C80 cm
- D0.5 cm
39.In a pinhole camera experiment, a student measures the image height for different object distances. The results are shown in the table. What is the relationship between image height and object distance?
Medium
- AImage height is directly proportional to object distance.
- BImage height is inversely proportional to object distance.
- CImage height is independent of object distance.
- DImage height is proportional to the square of object distance.
40.A student makes a pinhole camera with a box of length 20 cm. She places an object 60 cm from the pinhole. The image on the screen is 3 cm tall. She then moves the object to 30 cm from the pinhole. What is the new image height?
Hard
- A1.5 cm
- B6 cm
- C12 cm
- D0.75 cm

Revision notes

## Cameras - Revision Notes ### Pinhole Camera - A simple camera: a box with a **small hole** at one end and a **translucent screen** (e.g., tracing paper) at the other. - **Translucent**: allows some light to pass through. - Light rays travel in straight lines from the object through the pinhole. - The image is **inverted** (upside down) because rays from the top and bottom of the object travel at different angles. ### Modern Camera - Contains a **convex lens** that **refracts** light to a focus. - Instead of a retina, it has a **light-sensitive sensor**. - Even phone cameras have lenses and sensors. ### Key Comparisons - **Human eye vs. camera**: Both have a convex lens; the eye has a retina, the camera has a sensor. - **Pinhole vs. modern camera**: Pinhole has no lens; modern camera uses a convex lens to focus light. ### Refraction - **Refraction**: bending of light when it passes from one medium to another. - A convex lens bends light rays inward so they meet at a **focal point**. ### True/False Summary - Both eye and camera have convex lens: **True** - Eye has retina, camera has sensor: **True** - Pinhole camera has convex lens: **False** - Pinhole image is same way up: **False** (it is inverted)

Pinhole camera: A simple camera consisting of a box with a small hole at one end and a translucent screen at the other; produces an inverted image.
Translucent: A material that allows some light to pass through it.
Inverted: Upside down; the image is inverted in a pinhole camera.
Convex lens: A lens that refracts light rays to a focus; used in cameras and the human eye.
Refraction: The bending of light as it passes from one medium to another.
Sensor: The light-sensitive part of a camera, equivalent to the retina in the human eye.
Retina: The light-sensitive layer at the back of the human eye.

Flashcards

What is a pinhole camera?

A simple device that forms an image of an object using a box with a small hole at one end and a translucent screen at the other.

What material is typically used for the screen in a pinhole camera?

A thin, translucent material like tracing paper.

What does 'translucent' mean?

A material that allows some light to pass through it.

Why is the image in a pinhole camera inverted?

Because light rays from the top and bottom of the object travel at different angles, crossing over at the pinhole.

What does 'inverted' mean in the context of an image?

The image is upside down compared to the object.

How can you make a simple pinhole camera at home?

Using a shoebox and tracing paper.

What type of lens does a modern camera contain?

A convex lens.

What is the function of a convex lens in a camera?

It refracts light to a focus.

What is the light-sensitive part of a modern camera called?

A sensor.

What is the light-sensitive part of the human eye called?

The retina.

Do both the human eye and a camera contain a convex lens?

True.

Does the human eye contain a retina while a camera has a sensor?

True.

Does a pinhole camera contain a convex lens?

False. A pinhole camera uses a small hole, not a lens.

Are images formed by a pinhole camera always the same way up as the object?

False. They are inverted (upside down).

What is refraction?

The bending of light as it passes from one medium to another.

How does a convex lens refract light?

It bends light rays inward so they meet at a focal point.

What is the purpose of a lens in a camera?

To focus light onto the sensor to form a clear image.

What is the equivalent of a camera's sensor in the human eye?

The retina.

What is the equivalent of a camera's lens in the human eye?

The convex lens of the eye.

Do phone cameras contain lenses and sensors?

Yes, even very small cameras have lenses and sensors.

Unlock all 40 questions, flashcards & more

Create a free account to see every question, the slides, flashcards and revision notes for this topic.

Past papers

Past-paper practice for this topic is coming soon.

Coming soon