Magnification (AQA GCSE Physics)

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Magnification

  • The magnification of a lens is equal to the ratios of the image height and the object height

Magnification Equation, downloadable IGCSE & GCSE Physics revision notes
  • This equation can be rearranged with the help of a formula triangle:

Magnification Triangle, downloadable IGCSE & GCSE Physics revision notes

Magnification, image height and object height formula triangle

  • The magnification depends on:

    • The distance of an object from the lens

    • The power of the lens

  • The units for height are unimportant, provided that both the object and image are measured in the same units

    • For example, both in cm, or both in mm

  • Therefore, magnification does not have units as it is a ratio

  • If the magnification is:

    • > 1, then the image is magnified

    • = 1, then the object and image are the same size

    • < 1, then the image is diminished

Worked Example

A person sees an image from a magnifying glass.

Magnification Worked Example Questions, downloadable IGCSE & GCSE Physics revision notes

Calculate the magnification of this image. Clearly show your working on the diagram.

Answer:

Magnification Worked Example Solution, downloadable IGCSE & GCSE Physics revision notes

Step 1: Measure the height of the object from the scale

The object is 10 cm

Step 2: Measure the height of image from the scale

The image is 20 cm

Step 3: Substitute values into the magnification equation

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Ashika

Author: Ashika

Expertise: Physics Project Lead

Ashika graduated with a first-class Physics degree from Manchester University and, having worked as a software engineer, focused on Physics education, creating engaging content to help students across all levels. Now an experienced GCSE and A Level Physics and Maths tutor, Ashika helps to grow and improve our Physics resources.