8355963
Description
Flashcards by david doran, updated more than 1 year ago
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Created by david doran
about 7 years ago
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| Question | Answer |
| Define refraction | Refraction is the change of direction of light as it passes from one medium to another. |
| How does a lens form an image | A lens forms an image by refracting light |
| What is the refractive index ? | the degree to which light refract while passing through a given medium |
| How do we calculate the refractive index | i is the angle of incidence r is the angle of refractio |
| Describe the ray pattern of a converging lens lens | In a convex or converging lens, parallel rays of light are brought to a focus at the principal focus. |
| What is the focal length ? | The distance from the lens to the principal focus is called the focal length. |
| Describe the ray pattern of a diverging lens | A diverging lens makes parallel rays spread out as if they came from a point called the principle focus |
| How is a real image formed ? | A real image is formed by a converging lens if the object is further away than the principle focus |
| How is a virtual image formed ? | A virtual image is formed by a diverging lens and by a converging lens if the object is nearer to the lens than the principle focus . the image is MAGNIFIED |
| How do you calculate magnification of a virtual image ? | image height / object height |
| describe the image formed when an object is placed between a converging lens and F | the image formed is virtual , upright , magnified and on the same side of the lens as the object |
| What is the difference between a real and virtual image | A real image is the image formed where the light rays are focussed. A virtual image is one from which the light rays appear to come but don’t actually come from that image like in a mirror. You can project a real image onto a screen or wall, A virtual image can not be projected. |
| How does a camera for an image | it contains a converging lens that is used to form a real image of an object. Beyond 2F image is real , diminished and inverted |
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