Question

Short-Answer Questions
1. What is the refraction of light?
2. Define refractive index of a medium. 3. What are real and virtual images? Give one example of each
4. What are spherical mirrors?
5. What are the characteristics of an image formed by a convex mirror?
6. If an object is placed at the centre of curvature of a concave mirror, where will its image be formed?
7. If an object is placed at the focus of a concave mirror, where will its image be formed?
8. What is the relation between the focal length and the radius of curvature of a spherical mirror?
9. What is a spectrum?​

Answer 1

Answer:

1 Refraction is the bending of light (it also happens with sound, water and other waves) as it passes from one transparent substance into another. This bending by refraction makes it possible for us to have lenses, magnifying glasses, prisms and rainbows.

2 optics, the refractive index of a material is a dimensionless number that descThe best example of a real image is the one formed on a cinema screen. ...

3 The best example of a virtual image is your reflection in the mirror. Real images are produced by intersecting rays while virtual images are produced by diverging rays. Real images can be projected on a screen while virtual ones cannot.ribes how fast light travels through the material. It is defined as n={\frac {c}{v}}, where c is the speed of light in vacuum and v is the phase velocity of light in the medium.

4 A spherical mirror is a mirror which has the shape of a piece cut out of a spherical surface. There are two types of spherical mirrors: concave, and convex.

5 The image is virtual, erect and smaller in size than the object, but gets larger (maximum upto the size of the object) as the object comes towards the mirror. Such mirrors are also called diverging mirrors.

6 The image forms at the centre of curvature itself. The image is real, inverted and of the same size as the object.

7 As we can see, the image will be formed at infinity. Hence, point a is correct. Since, the image is formed at infinity, it will be highly magnified.

8 The relation between focal length (f) and radius of curvature (R) of a spherical mirror is that the focal length is equal to half of the radius of curvature i.e. f=R2

9 spectrum (plural spectra or spectrums) is a condition that is not limited to a specific set of values but can vary, without steps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors in visible light after passing through a prism.

Answer 2

1. When light travels from air into water, it slows down, causing it to change direction slightly. This change of direction is called refraction.

or

The bending of light is known as refraction.

2. The refractive index is the measure of bending of a light ray when passing from one medium to another i.e. from air to water.

3.Real images are the images which can be obtained on the screen.

AND

virtual images are the images which cannot be obtained on the screen

OR

The image formed when rays of light meet at a point after reflection/refraction is called real image. The image formed when rays of light appear to meet (when diverging rays are extended) at a point is called a virtual image. ... Real images are inverted

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