People suffering from both myopia and hypermetropia, needs ............. lens

The point inside the lens on the principal axis through which light rays pass without changing their path is called

The capacity of a lens to converge or diverge incident rays is called .............. of the lens.

Principal focus of a magnifying glass is

............ is a combination of two convex lenses with small focal length.

For the normal human eye, minimum distance of distinct vision is ............. cm.

A person suffering from hypermetropia

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?

There is a small hole of changing diameter at the centre of the iris which is called

The capacity of the lens to change its focal length as per need is called as

A type of lens which has two spherical surfaces which are puffed up outwards is .............. .

For a myopic eye, the defect is cured by .............. .

............ helps the eye lens to adjust the focal length depending on the distance of the object by contracting or relaxing.

The farthest distance of an object from a human eye, at which it is clearly visible without stress on the eye is called

Which of the following is wrong? Here M represents magnification of a lens.

An optical instrument, in general, extends our range of vision by

When two lenses are kept touching each other, the power of the combined lens is equal to

The colour of the eye is determined by

Retina of eye corresponds to which part of camera?

The final image produced by a simple microscope is

If magnification of a lens is 10 then which of the following is correct?

In relaxed position of eye muscles, the focal length of healthy eye lens is about

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

The image obtained while finding the focal length of convex lens is

Power of lens is

At what distance a watch maker must hold his lens from the watch?

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?

When we see an object, the image formed on the retina is

The compound microscope is used to see

An object is kept at 20 cm from a convex lens of focal length 15 cm. The position of the image is

For the same thickness of the lens, if the radius of curvature is increased, the focal length will

The focal length of a concave lens, according to Cartesian sign conventions is

Magnification of the lens is always positive for

The minimum distance of an object from a human eye, at which it is clearly visible without stress on the eye is called

The direction of the ray passing through a lens changes because of the

A convex lens of short focal length held very close to the eye, to observe minute objects clearly is called as

The power of spectacles for hypermetric person

A focal length of a lens is 20 cm. What is power of a lens in dioptre?

The ............. cells respond to the colour and give information about the colour of the object to the brain.

Bifocal lens is required to correct ............... defect.

A convex lens forms a virtual image of an object placed ............. .

An object is placed at a distance of f/2 from a convex lens of focal length f. The image will be

Colour blindness indicates lack of

A ............... lens always produces virtual and diminished image.

A type of lens which is thinner at centre than at edges is........ .

Distance between optical centre and centre of curvature is called as .............. ..

A ray of light gets refracted ............... while entering the lens

To obtain an image of the same size as that of an object using a convex lens, the object should be placed

Defective refraction by the lenses causes

According to Cartesian sign conventions, all the distances are measured from the