Download to read offline
More Related Content
LENSES.pptx
- 1.
- 2. What are lenses? Lensescame from the Latin word for “lentil”, a type of bean used in cooking
- 3. How do lenseswork? •Refraction is the bending of light as it passes from one transparent substance into another. Refracted rays light rays
- 5. Types of lenses ConcaveLens Convex Lens * It is thicker at the center than the edges * It forms real images and virtual images depending on the position of the object. • It is thicker at the edges and thinner at the center • It forms upright, reduced image and virtual image
- 6. Types of lenses ConvexLens A convex lens is also called converging lens because it makes parallel light rays passing through it bend inward and converge at a spot just beyond the lens know as focal point (F)
- 7. Types of lenses ConcaveLens A concave lens is sometimes called diverging lens because it makes parallel light rays curve outward or diverge
- 8. Ray Diagramming forLenses
- 9. V F F 2F 2F Imaginaryline that will serve as guide when to bend the refracted ray in graphical method • Vertex (V) – the geometric center of a lens • Focal /Focus (F)- The point where light rays converge or appear to converge when parallel rays pass through a lens • Focal length- the distance from the vertex to the focal point note: twice the focal length you have 2f , which will help you in describing the image FORM BY A LENS f f
- 11. In Front andBack Side of a Lens
- 12. Three Most usefulRays for ray Diagramming for Lenses Where: P- Parallel ray F- Focal Point/Focus V- Vertex P-F Ray F-P Ray V- Ray At least two of these rays can be used to describe the images formed by a lens
- 13. Three Most usefulRays in Lenses Convex Lens Concave Lens A ray of light parallel to the principal axis is refracted passing though the principal focus, F located behind the lens A ray of light parallel to the principal axis is refracted passing though the principal focus, F located in front of the lens V F F P-F Ray V F F P–F Ray
- 14. Three Most usefulRays in Lenses Convex Lens Concave Lens A ray of light passing through the focus, F in front of the lens is refracted parallel to the principal axis. A ray of light directed towards the focus, F behind the lens is refracted parallel to the principal axis. V F F F-P Ray V F F F- P Ray Imaginary extension of the refracted ray
- 15. Three Most usefulRays in Lenses Convex Lens Concave Lens A ray of light passing through the vertex, V of a the lens and continue to travel in the same direction. V F F V-Ray V F F
- 17. Describing the Characteristicsof the images formed by lenses Location of the Image Between F and 2F Behind the lens Between V and F At F Beyond F and farther than 2F At 2F In front of the lens (if the image is virtual) Orientation of the Image Upright or Inverted
- 18. Describing the Characteristicsof the images formed by lenses Size of the Image Same, Reduced, Enlarged Type of the Image Real Image or Virtual Image
- 19. Difference between REALOR VIRTUAL REAL IMAGE VIRTUAL IMAGE Inverted image Positive (+) value of the distance of image (d ) Negative (-) value of the height of image (-h1) (means inverted, therefore real image) Negative (-) value of the magnification (-M) (means real image) Formed in front of a lens and CAN BE projected on a screen Upright image Negative (-) value of the distance of image (-d) Positive (+) value of the height of image (h) (means upright, therefore virtual image) Positive (+) value of magnification (M) (means virtual image) Formed in front of a lens and CANNOT be projected on a screen
- 20. Sample Ray Diagrammingof Convex Lens Note: the image will be drawn inverted if the refracted rays merge or converge in the lower or below the principal axis 1.Using a ruler and a pencil, draw the principal axis on a piece of paper. 2.Draw the lens and then a vertical line that crosses lens. 3.Mark two important points in the principal axis, the Vertex, Focal Point/Focus, and the 2F (twice the value of focal length). 4.Draw the object in front of the lens based on the given location. 5.From the tip of the object, draw at least two of these rays : P-F Ray, F-P ray, or V ray 6.From the point where the actual refracted rays merged to the principal axis, draw the inverted image of the object.
- 22. Sample Ray Diagrammingof Convex Lens Describe the Characteristics of the Image Formed Location of the Image Orientation of the Image Size of the Image Type of Image Behind the lens (between F and 2F) Inverted reduced Real Image
- 23. Sample Ray Diagrammingof Concave Lens 1.Using a ruler and a pencil, draw the principal axis on a piece of paper. 2.Draw the lens and then a vertical line that crosses lens. 3.Mark two important points in the principal axis, the Vertex, Focal Point/Focus, and the 2F (twice the value of focal length). 4.Draw the object in front of the lens based on the given location. 5.From the tip of the object, draw at least two of these rays : P-F Ray, F-P ray, or V ray 6.From the point where the virtual refracted rays merged to the principal axis, draw the upright image of the object. Note: the image will be drawn upright if the virtual refracted rays merge or converge in the upper or above the principal axis
- 25. Sample Ray Diagrammingof Convex Lens Describe the Characteristics of the Image Formed Location of the Image Orientation of the Image Size of the Image Type of Image In front the lens (same side where the object is located) Upright Reduced Virtual Image