Questions and Answers
Why does the sun appear white at noon?
Which phenomenon is responsible for the twinkling of stars?
What is the main reason the sky appears blue?
Why are danger signals on tall buildings often red?
Signup and view all the answers
Which of the following statements about the scattering of light is TRUE?
Signup and view all the answers
Which of the following scenarios would result in the LEAST amount of light scattering?
Signup and view all the answers
Which of the following is NOT a factor that influences the scattering of light?
Signup and view all the answers
Which of the following colors of light is scattered the LEAST by the atmosphere?
Signup and view all the answers
Which of the following statements BEST describes the relationship between the color of the sky and the scattering of light?
Signup and view all the answers
If the atmosphere were to completely absorb all colors of light, what color would the sky appear?
Signup and view all the answers
Study Notes
Light, Reflection, and Refraction
- A concave mirror of focal length 20 cm will produce a real and inverted image with a magnification of -2 if the object is at a distance of 30 cm from the pole.
- The focal length of a plane mirror is infinity.
- A concave spherical mirror of radius of curvature 120 cm will produce an erect image four times the natural size if the object is at a distance of 240 cm from the mirror.
- When a light ray enters from medium A to medium B, the refractive index of medium B relative to A is greater than unity.
- A 2cm pin placed 10 cm in front of a concave mirror of focal length 10 cm will produce an erect image 4 cm in height.
Mirrors and Lenses
- A concave mirror has a centre of curvature, pole, and focus, whereas a convex lens has a principal axis, focus, and radius of curvature.
- A concave lens having 4 dioptre power has a focal length 0.25 m, whereas a concave lens having -4 diopter power has a focal length -0.25 m.
- When a ray of light travels from a rarer medium to a denser medium, it bends towards the normal.
- The path of a ray of light passing through a rectangular glass slab is traced by drawing a straight line.
Lenses and Image Formation
- A convex lens of focal point 15 cm has a power of 6.67 D.
- A combination of a convex lens of power +3.5 D and a concave lens of power -2.5 D will behave like a convergent lens of focal length 200 cm.
- A device X that forms an image of a distant object on a white screen at a distance of 30 cm is a convex lens of focal length 15 cm.
- A convex lens forms a virtual image of an object placed at a distance of 20 cm, and the focal length of the lens must be greater than 20 cm and less than infinity.
Refraction and Dispersion
- When a ray of light passes from air into a denser medium, it deviates towards the normal.
- A glass slab placed over a page with printed letters will raise the image of the letters, with the letter V raised the most.
- A rainbow is caused by the dispersion of sunlight from water drops.
- When sunlight enters a glass prism, it is deviated and dispersed.
- The clear sky appears blue because blue light is scattered more than other colours by the atmosphere.
Optical Instruments and Defects
- A person who cannot see objects beyond 2 m can be corrected using a lens of power -0.5 D.
- Twinkling of stars is due to the refraction of light by different layers of the atmosphere with varying refractive indices.
- The danger signals installed at the top of tall buildings are red in colour because red light is scattered the least by smoke or fog.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your understanding of light reflection, refraction, and image formation with concave and plane mirrors. Learn about focal lengths, magnification, and refractive indices.