Lesson T4.2.3

T4.2.3 Mirrors, pinhole cameras and lenses Quiz: KS3 Physics, Unit 4

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson T4.2.3, Mirrors, pinhole cameras and lenses: 20 multiple choice questions for the KS3 Physics (National Curriculum), Unit 4: Waves, written with Revision Ninja.

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The 20 questions

  1. What model of light is used to explain mirrors, pinhole cameras and lenses?

    • The wave model of sound, in which light compresses the air and makes it ring as it passes.
    • The particle model, in which light is made of solid balls that bounce off the mirror surfaces.
    • The ray model, in which light travels in straight lines.
    • The electric model, in which light is a current that flows along the surface of the mirror.

  2. Why is the image in a pinhole camera upside down?

    • Light from the top and bottom of the object cross over at the pinhole.
    • The pinhole reverses the colours of the image, which also turns the picture the wrong way up.
    • Light bends upwards when it passes through a hole, which flips the image over as it goes through.
    • The image is inverted by the film inside the camera, which turns the picture over as it is recorded.

  3. What is the image formed in a plane mirror?

    • Real, upright and smaller than the object, which can be projected onto a wall behind the mirror.
    • Virtual, inverted and twice the size of the object, which appears to be floating above the mirror.
    • Real, inverted and larger than the object, which can be caught on a screen placed in front of it.
    • Virtual, upright, the same size as the object and laterally inverted.

  4. A person stands 2 m in front of a plane mirror. How far is their image from the mirror?

    • 2 m
    • 4 m, which is found by adding the person's distance to the mirror and the image distance together
    • 0.5 m, which is found by dividing the distance by four, as if the mirror were at the centre
    • 1 m, which is found by halving the distance from the person to the mirror as a shortcut

  5. What does a convex lens do to parallel rays of light?

    • It turns them into sound waves, which carry the energy of the light away from the lens.
    • It brings them together at a focal point.
    • It spreads them out so they never meet, which makes the rays diverge from one another.
    • It absorbs them and makes the lens warm, which stops the rays from passing through the lens.

  6. Which type of lens is thicker in the middle than at the edges?

    • A concave lens, which is thinner in the middle and thicker towards its outer edges instead
    • A flat sheet of glass, which has the same thickness across its whole area and no curve at all
    • A convex lens
    • A plane mirror, which is a flat reflecting surface with no thickness that varies across it

  7. What is a pinhole camera?

    • A device that uses sound waves to form an image, which are then printed onto photographic paper.
    • A camera with a lens that focuses light onto a digital sensor at the back of the camera body.
    • A light-tight box with a small hole in one side that forms an image on the opposite wall.
    • A camera that stores light as a magnetic pattern, which is later decoded into a picture on screen.

  8. Why does a larger pinhole make a brighter but blurrier image in a pinhole camera?

    • A larger hole stops light from entering the camera, which makes the image darker and less clear.
    • A larger hole turns the image into a sound pattern, which is why the picture becomes blurry.
    • A larger hole makes light travel more slowly, which spreads the image out across the far wall.
    • A larger hole lets in more light but allows rays from more points to overlap.

  9. Which description of an image in a plane mirror is correct?

    • It is the same size as the object and appears to be behind the mirror.
    • It is larger than the object and appears in front of the mirror, between the mirror and the viewer.
    • It is smaller than the object and cannot be seen by the viewer at any position in front of it.
    • It is always inverted, so it cannot be used to see yourself when you look into the mirror.

  10. What causes a convex lens to focus light?

    • The lens increases the speed of light in air, which makes the rays arrive at one point together.
    • The lens stops the light from travelling further, which concentrates it at the lens surface.
    • The lens bends light rays towards each other as they pass through.
    • The lens absorbs all the rays and then emits them again from a single point on the far side.

  11. In a pinhole camera, what happens if the object moves closer to the pinhole?

    • The image disappears entirely, because the object is then too close for light to pass the hole.
    • The image on the far wall becomes smaller, because the rays from the object spread less far.
    • The image on the far wall becomes larger.
    • The image moves to the side of the box, because the closer object shifts the rays sideways.

  12. What is the purpose of the lens in a magnifying glass?

    • It stores light so the object glows brightly in the dark, which makes it easier to see clearly.
    • It absorbs light so the object looks darker and more detailed when viewed through the lens.
    • It bends light to make a larger, upright, virtual image of a close object.
    • It turns the object into a sound source, which makes it audible when it is viewed through the glass.

  13. Why do mirrors appear to reverse left and right?

    • Light travels backwards through the mirror, which reverses the sides of the image as it passes.
    • The image is laterally inverted, meaning the reflection is a mirror image of the object.
    • The mirror bends light so that the image turns over, which swaps the left and right sides.
    • The mirror inverts the image top to bottom, which makes the left and right sides look swapped.

  14. Which statement best explains why a pinhole camera image needs no lens?

    • A pinhole bends the light into focus using a hidden lens, which is too small to see by eye.
    • A small hole allows only one ray from each point of the object through, forming a sharp image.
    • The camera stores the image in a magnetic pattern, which means that no focusing is needed.
    • The image is formed by sound waves rather than light, so it does not need a lens to focus.

  15. What is the focal point of a convex lens?

    • The point where parallel rays of light meet after passing through the lens.
    • The centre of the lens's curved surface, which is the midpoint of the lens's thickness.
    • The place where the lens stops working, which is the furthest point at which light can pass.
    • The point where light is absorbed by the lens, which then becomes hot and begins to glow.

  16. A ray of light strikes a plane mirror. Which statement about the reflected ray is correct?

    • It leaves the mirror at a right angle to the mirror surface, whatever angle the ray arrived at.
    • It leaves the mirror at the same angle to the normal as the incident ray.
    • It is absorbed by the mirror and does not return to the viewer, which is why mirrors look dark.
    • It travels through the mirror at the same speed, which lets it emerge on the far side of the glass.

  17. Why are lenses used in eyeglasses?

    • They turn light into sound so the eye can hear it, which allows the wearer to hear distant objects.
    • They make light travel faster through the eye, which allows the eye to see objects more quickly.
    • They absorb light so the eye is protected, which stops the eye from being damaged by bright light.
    • They bend light so that it is focused correctly on the retina.

  18. Which of these uses a convex lens to form an image?

    • A projector that makes an enlarged image on a screen
    • A flat mirror in a bathroom, which forms a same-size image without using any lens at all
    • A pinhole in a cardboard box, which forms an image without any lens of any kind
    • A plain glass window in a house, which lets light pass straight through without forming an image

  19. What is the name for an image that can be projected onto a screen?

    • A diffuse image, which is spread out over the screen without being focused on any point
    • A laterally inverted image, which is reversed left to right by a mirror or lens in use
    • A virtual image, which only appears to be at a place where the viewer's eye sees it
    • A real image, formed where the light rays actually meet

  20. Why does a convex lens make a bright spot when sunlight is focused onto paper?

    • It reflects sunlight away from the paper so that the area under the lens goes dark
    • It spreads the sunlight out evenly across the paper so that the paper cools down quickly
    • It absorbs the sunlight and turns it into a magnetic field that lies across the paper
    • It focuses many parallel rays of sunlight onto one small point, concentrating the energy.

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