How to Draw Concave Lens Ray Diagrams

Real & Virtual Images

• Images produced by lenses tin be one of two types:
  • A real image
  • A virtual prototype

Real Images

• A existent image is defined as:

An prototype that is formed when the light rays from an object converge and meet each other and tin can be projected onto a screen

• A real image is ane produced by the convergence of low-cal towards a focus
• Real images are e'er inverted
• Existent images tin be projected onto pieces of paper or screens
  • An example of a real image is the image formed on a cinema screen

A existent image can be projected onto a screen

• Real images are where ii solid lines cross in ray diagrams

Virtual Images

• A virtual image is defined as:

An image that is formed when the light rays from an object do not meet just appear to meet backside the lens and cannot be projected onto a screen

• A virtual epitome is formed past the divergence of light abroad from a indicate
• Virtual images are always upright
• Virtual images cannot exist projected onto a slice of paper or a screen
  • An example of a virtual image is a person's reflection in a mirror

A reflection in a mirror is an example of a virtual epitome

• Virtual images are where two dashed lines, or ane dashed and one solid line crosses in ray diagrams

Convex & Concave Ray Diagrams

• Lenses can be used to form images of objects placed in forepart of them
• The location (and nature) of the image can be found by drawing a ray diagram:

Convex Lens Ray Diagrams

• If an object is placedfurther from the lens than the focal lengthf then arealimage will be formed, and the converging lens ray diagram will be drawn in the following style:

Diagram showing the formation of a real image by a lens

1. Start by drawing a ray going from the top of the object through the centre of the lens. This ray will continue to travel in a directly line
2. Next draw a ray going from the summit of the object, travelling parallel to the axis to the lens. When this ray emerges from the lens information technology will travel direct through the chief focus f
3. The image is the line drawn from the axis to the point where the above 2 rays meet

• When describing an image, consider if it is:
  • Existent or virtual
  • Magnified (larger) or diminished (smaller)
  • Upright or inverted

• For case, in the in a higher place diagram, the image is:
  • Real: the lite rays run across each other after refraction
  • Magnified: the image is larger than the object
  • Inverted: the image is formed on the contrary side of the primary axis

• A convex lens will produce a real image of an object which is placed at a distance greater than the focal length from the lens
• If the object is placed closer to the lens than the focal length f then a virtual prototype will exist formed and the converging lens ray diagram will be fatigued in the post-obit way:

A virtual paradigm formed when the object is placed closer than the focal length

1. Commencement past cartoon a ray going from the top of the object through the centre of the lens. This ray will continue to travel in a straight line
2. Draw a dashed line standing this ray upwards
3. Side by side draw a ray going from the top of the object, travelling parallel to the centrality to the lens. When this ray emerges from the lens it volition travel direct through the principal focus f
4. As well, describe a dashed line continuing this ray upwards
5. The image is the line drawn from the centrality to the betoken where the two dashed lines run across

• In this instance, the paradigm is:
  • Virtual: the light rays appear to see when produced backwards
  • Magnified: the image is larger than the object
  • Upright: the paradigm is formed on the same side of the principal axis

Concave Lens Ray Diagrams

• Concave (diverging) lenses tin too be used to form images, although the images are always virtual in this example
• If an object is placedfurther from the lens than the focal length f then a concave lens ray diagram volition be fatigued in the following way:

Concave lenses only produce virtual images

1. Start by drawing a ray going from the top of the object through the centre of the lens. This ray will continue to travel in a direct line
2. Next draw a ray going from the top of the object, travelling parallel to the axis to the lens. When this ray emerges from the lens it will travel directly upwards away from the centrality
3. Draw a dashed line continuing this ray downwards to the focal bespeak, f
4. The image is the line drawn from the axis to the point where the above two rays meet

• In this case, the image is:
  • Virtual: the light rays appear to meet when produced backwards
  • Diminished: the epitome is smaller than the object
  • Upright: the image is formed on the same side of the principal axis

Comparing Convex & Concave Lenses

• The image produced by a convex lens can be either real or virtual
  • This means the prototype tin be inverted (real) or upright (virtual)
• The epitome produced by a concave lens is always virtual
  • This means the image will always be upright

Worked Case

An object is placed exterior the focal point of a concave lens.Consummate the ray diagram past cartoon where the prototype of this object volition be seen.

Step 1: Draw a line from the top of the object through the middle of the lens

• • The elevation of the image lies somewhere forth this line

Step ii: Draw a line from the focal point through the peak of the lens

• • The dashed line shows the continuation of the up arrow
  • The top of the image is where the two lines cross

Exam Tip

The best style to remember these ray diagrams is to depict them and see the results for yourself. Remember to always apply a ruler or a direct edge in the exam when drawing the rays to proceeds total marks and produce the virtually accurate drawings

How to Draw Concave Lens Ray Diagrams

Source: https://www.savemyexams.co.uk/notes/gcse-physics-aqa-new/waves/optics/6-3-2-convex-concave-ray-diagrams/

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