P5 - Magnification, Cameras and Projectors

Question 1

What lens do magnifying glasses use to create magnified images?

Answer 1

• Magnified glasses use convex lenses to create magnified images.

Question 2

What is required for the image to be produced using magnifying glasses?

Answer 2

• The object being magnified must be closer to the lens than the focal length.

Question 3

What type of image is produced by magnifying glasses?

Answer 3

• Magnifying glasses produce virtual images.

Question 4

What happens when you take a photograph of a flower?

Answer 4

When you take a photograph of a flower, light from the object ( flower ) travels to the camera and is refracted by the lens, forming an image on the light sensor ( or film in old cameras ).

Question 5

What are some features of the image produced by a camera?

Answer 5

• The image is inverted, upside down.
• The image is real, because the light rays actually meet there
• The image is smaller than the object, because the object’s a lot further away than the focal length of the cameras.

Question 6

What are some features of a projector image?

Answer 6

• The image is a lot closer than the focal length of the lens, so the image is larger.
• When you project an image, the object needs to be placed upside down and very close to the lens.
• Light from the object is refracted by the lens and produces a real, inverted and magnified image on-screen.

Question 7

When will an image be in focus?

Answer 7

An image will be in focus when the light that forms the image converges on the screen or sensor.

Question 8

How are images focused in cameras & projectors?

Answer 8

• Image is focused by moving the lens closer to, or further from the object.
• The closer to the object the lens is, the further from the lens the image will be formed ( and vice versa ).

Question 9

What is the magnification formula?

Answer 9

Image Size/Object Size.

This tells you the magnification produced by a lens.