Flash Card
The capacity of a lens to converge or diverge incident rays is called .............. of the lens.
The point inside the lens on the principal axis through which light rays pass without changing their path is called
A student obtained a clear image of window bars on a screen with the help of a convex lens. But in order to have the best image, his teacher suggested him to obtain the image of a distant tree. Where will the lens have to be moved in order to obtain a clear image?
For the same thickness of the lens, if the radius of curvature is increased, the focal length will
When the distance between the eye-lens (crystalline-lens) and retina is more, the normal distance image is formed in front of the retina, such an eye defect is called as
............ helps the eye lens to adjust the focal length depending on the distance of the object by contracting or relaxing.
For a specific glass lens f = 0.5 m. This is the only information given to the student. Which type of lens is given to him and what is its power?
An object is placed at a distance of f/2 from a convex lens of focal length f. The image will be
The minimum distance of an object from a human eye, at which it is clearly visible without stress on the eye is called
The ............. cells respond to the colour and give information about the colour of the object to the brain.
The farthest distance of an object from a human eye, at which it is clearly visible without stress on the eye is called
An object is kept at 20 cm from a convex lens of focal length 15 cm. The position of the image is
A type of lens which has two spherical surfaces which are puffed up outwards is .............. .