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

Retina of eye corresponds to which part of camera?

Principal focus of a magnifying glass is

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

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

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

Magnification of the lens is always positive for

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

The final image produced by a simple microscope is

The power of spectacles for hypermetric person

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

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

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

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

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

Defective refraction by the lenses causes

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

The colour of the eye is determined by

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

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

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

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

A person suffering from hypermetropia

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

The compound microscope is used to see

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

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

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

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

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

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

Power of lens is

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

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

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

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

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

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

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?

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

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

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

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

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

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

Colour blindness indicates lack of

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

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