Refraction by Spherical Lenses

The following data-was recorded for values of object distance and the corresponding values of image distance in the experiment on study of real image formation by a convex lens of power $+5 \mathrm{D}$.

An object of height $3 \mathrm{cm}$ is placed at $10 \mathrm{cm}$ from a concave lens of focal length $15 \mathrm{cm}$. Select the correct size of the image.

An object is placed at a distance $20 \mathrm{cm}$ from a convex lens of focal length $10 \mathrm{cm}$. Select the correct image distance and nature of the image.

The convex lens always gives small virtual image.

The power of lens depends on the focal length of the lens.

An object is kept at a distance of $30 \mathrm{cm}$ from a diverging lens of focal length $15 \mathrm{cm}$. At what distance the image is formed from the lens? Find the magnification of the image.

A lens may have two spherical surfaces, bulging outwards. Such a lens is called a convex lens. It is thicker at the middle as compared to the edges. A concave lens is bounded by two spherical surfaces, curved inwards. It is thicker at the edges than at the middle. Answer the following question.

The nature of images formed by two lenses are given.
(i) An erect and magnified virtual image
(ii) An erect and diminished virtual image

To get an image having the same size as the object, what is the position of the object?

A lens may have two spherical surfaces, bulging outwards. Such a lens is called a convex lens. It is thicker at the middle as compared to the edges. A concave lens is bounded by two spherical surfaces, curved inwards. It is thicker at the edges than at the middle. Answer the following question.

The nature of images formed by two lenses are given.
(i) An erect and magnified virtual image
(ii) An erect and diminished virtual image

By using which type of lens will we get an image having the same size as the object?

A lens may have two spherical surfaces, bulging outwards. Such a lens is called a convex lens. It is thicker at the middle as compared to the edges. A concave lens is bounded by two spherical surfaces, curved inwards. It is thicker at the edges than at the middle. Answer the following question.

The nature of images formed by two lenses are given.
(i) An erect and magnified virtual image
(ii) An erect and diminished virtual image

What type of lens is used in the second case?

Assertion: Virtual images are always erect.

Reason: Virtual images are formed by diverging lenses only.

Name the lens whose thickness cannot be deemed negligible.

The lens whose thickness is not negligible is known as thin lens.

What do you mean by thick lens?

The lens is always formed from a sphere. What is the name of the centre of the sphere called?

What is the centre of the sphere from which the lens is formed called?

The centre of curvature is the centre of the sphere from which the lens is made.

What is centre of curvature of a lens?

A small object is placed in front of convex lens of focal length $25 \mathrm{cm}$ , such that a virtual image is formed at a distance of $25 \mathrm{cm}$. The magnification produced is 

A _____ (convex / concave) lens can produce both real and virtual images.

At what distance from a convex lens of focal length $24 \mathrm{cm}$, should an object be placed so that the lens forms an image of the same size as the object?