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Nov 16, 2013



Dec 3, 2014

#### What is the difference between a virtual image and a real image?



real image is formed when the light rays really meet, whereas virtual image is formed when the light rays appear to meet.

Jan 19, 2014

#### uses of convex lens in daily life.,.



It is converging lens . Used in magnifying g...

Mar 3, 2015



Jan 28, 2015

#### If the speed of light in vacuum is 3x10⁸ m/s, find the speed of light in a medium of absolute refractive index 1.5.



Refractive index of a medium = Speed of light in vacuum/Speed of light in a medium

1.5 = 3 x 108

Mar 3, 2015



Nov 21, 2013



Dec 5, 2014

#### An object 5 cm in size is placed at a distance of 20 cm from the concave mirror of focal length 15 cm. At what distance from the mirror should a screen be placed to get a sharp image? Also find the height of the image.



Object-size, h = + 5.0 cm;
Object-distance, u = – 20.0 cm;
Focal length, f = –15.0 cm;
Image-distance, v = ?
Image-size, h′ = ?
Mirror formula is ...

Dec 4, 2014

#### What for concave and convex mirrors and lenses are used?



Uses of Concave Mirrors
• Concave mirrors are used as shaving mirrors to see a larger image of the face.
• Dentists use concave mirrors to view the back of the tooth. ENT doc...