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### SIGN CONVENTION

We follow the ‘new Cartesian sign convention’. The pole of the mirror is taken to be at origin of the rectangular coordinate system. Accordingly, we shall use the following convention regarding the sign of various quantities. (a) All distances are measured from pole of mirror. (b) The distances measured in the same direction as the […]

### RELATION BETWEEN ‘RADIUS’ AND ‘FOCAL LENGTH’ OF A SPHERICAL MIRROR

Let us consider a parallel beam of light falls on concave and convex mirrors. The law of reflection are applied at each point. The normal to the surface at the point ‘M’ is ‘CM’. After reflection, the ray converges to the point ‘F’ (as in the case of convex mirror). Let incident ray makes an […]

### GRAPHICAL METHOD FOR FORMATION OF IMAGE BY SPHERICAL MIRRORS

(a) Concave mirror: Case 1: when object is at infinity. Case 2: when object is beyond ‘c’. Case 3: when object is at ‘c’. Case 4: When object is between ‘c’ and ‘F’. Case 5: When object is at ‘F’. Case 6: When object is between pole and focus. (b) Convex mirror: Case 1: When […]

### FORMATION OF IMAGES BY SPHERICAL MIRRORS

The best method for formation of images by mirror is through ray tracing. The point at which reflected rays will intersect gives the location of images. (a) A ray parallel to the axis, after reflection, passes through the focal point of a concave mirror or appears to come from the focal point of a convex […]

### SPHERICAL MIRRORS:

SPHERICAL MIRRORS: Spherical mirror are part of spherical reflecting surfaces. It has two types: (1) Concave mirror: When the reflection takes place from inner surface (polished or silvered on outer surface) called concave mirror or converging mirror. (2) Convex mirror: When the reflection takes place from outer surfaces (polished or silvered on inner surface) called […]

### TELESCOPE

It is used to provide angular magnification of the distant objects. It is of two types: (1) Retracting type telescope (2) Reflecting type telescope RETRACTING TYPE TELESCOPE: It is of two types. (a) Astronomical telescope (b) Terrestrial telescope A telescope used to see heavenly bodies is called astronomical telescope. It produces a virtual and inverted […]

### DISPERSION

The phenomenon of splitting of light into its component colours is known as dispersion. SPECTRUM: The pattern of colour components of light is called the spectrum. ANGULAR DISPERSION: “The angle between the two rays corresponding to the extreme colours red and violet in the spectrum is called angular dispersion”. DISPERSIVE POWER: The ratio of angular […]

### SCATTERING OF LIGHT IN ATMOSPHERE

When sunlight travels through the earth’s atmosphere, it get scattered by the large number of molecules present. This scattering of sunlight is responsible for the colour of the sky, colour during sunrise and sunset etc. According to Ray leigh’s criterian, the amount of scattering is inversely proportional to the fourth power of wavelength known as […]

### THE RAINBOW

When sunlight falls on small water droplets suspended in air during or after rain, it suffers refraction, total internal reflection and dispersion. The condition for observing a rainbow are that the sun should be at the back of an observer and the water droplets in front. Sunlight is first refracted when it enters a rain […]

### REFLECTION OF LIGHT

Definition: When a light ray strikes the boundary between two media such as air and glass, a part of that light is reflected. By reflection we mean the bouncing back of the radiant energy at the boundary between the two media and this is the reason for the visibility of non–luminous bodies. LAWS OF REFLECTION: […]

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