Explain the Following Term Related to Spherical Lenses:- Aperture - Science


Explain the following term related to spherical lenses:- aperture




The diameter of sphere of part of which a lens is formed is called the aperture.

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2013-2014 (March) All India Set 3

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A simple microscope is used by watch repairers. Give reason.

Explain the following term related to spherical lenses:- centres of curvature

Fill in the blanks:

Image formed by a convex ________ is always virtual and smaller in size.

Fill in the blanks:

An image formed by a ________ mirror is always of the same size as that of the object.

Mark ‘T’ if the statement is true and ‘F’ if it is false:

We can obtain an enlarged and erect image by a convex mirror. (T/F)

Mark ‘T’ if the statement is true and ‘F’ if it is false:

A concave mirror always forms a real image. (T/F)

Match the items given in Column I with one or more items of Column II.

Column I Column II
A plane mirror Used as a magnifying glass.
A convex mirror Can form image of objects spread over a large area.
A convex lens Used by dentists to see enlarged image of teeth.
A concave mirror The image is always inverted and magnified.
A concave lens The image is erect and of the same size as the object.
  The image is erect and smaller in size than the object

Find out the letters of English alphabet or any other language known to you in which the image formed in a plane mirror appears exactly like the letter itself. Discuss your findings.

Give one use each of a concave and a convex mirror.

Which type of mirror can form a real image?

A virtual image larger than the object can be produced by a

Define Radius of curvature of the spherical mirror

Define the Focal length of a spherical mirror

Name the spherical mirror which has:

(a) virtual principal focus.
(b) real principal focus.

Define (a) centre of curvature (b) radius of curvature (c) pole (d) principal axis, and (e) aperture, of a spherical mirror with the help of a labelled diagram

When a spherical mirror is held towards the sun and its sharp image is formed on a piece of a carbon paper for some time, a hole is burnt in the carbon paper. 

 At which point of the spherical mirror the carbon paper is placed?

Name the spherical mirror which can produce a real and diminished image of an object.

Name the spherical mirror which can produce a virtual and diminished image of an object.

Write the formula for a lens connecting image distance (v), object distance (u) and the focal length (f). How does the lens formula differ from the mirror formula?                         

A 50 cm tall object is at a very large distance from a diverging lens. A virtual, erect and diminished image of the object is formed at a distance of 20 cm in front of the lens. How much is the focal length of the lens?

A ray of light travels from a denser medium to a rarer medium. How will it bend?

What do you mean by the term dispersion?

What is a spherical mirror?

State the two kinds of spherical mirror and distinguish them with the aid of proper diagrams.

Explain the following terms : 
Pole, Centre of curvature, Radius of curvature, Principal axis. Show them on separate diagrams for each of the concave and convex mirrors.

State the direction of incident ray which after reflection from a spherical mirror gets reflected along its own path. Give a reason.

Which are the two convenient rays that are chosen to construct the image by a spherical mirror for a given object? Explain with the help of suitable ray diagrams.

Draw separate diagrams for the formation of virtual image of an object by convex mirror. State the difference between concave and convex image.

Name the kind of mirror used to obtain
(a) a real and enlarged image
(b) a virtual and enlarged image
(c) a real and diminished image, and
(d) a virtual and diminished image.

If a spherical mirror breaks, what type of mirrors are the individual pieces?

Three mirrors are created from a single sphere. Which of the following - pole, centre of curvature, radius of curvature, principal axis - will be common to them and which will not be common? 

Write the spherical mirror's formula and explain the meaning of each symbol used in it.

State two uses of a concave mirror. 

The image formed by a convex mirror is of size one third the size of object. How are u and v related?

An object of length 4 cm is placed in front of a concave mirror at distance 30 cm. The focal length of mirror is 15 cm.

  1. Where will the image form?
  2. What will be the length of image?

A straight stick partly dipped in water obliquely, appears to be bent at the surface of water.

Choose the correct alternative and rewrite the following:

Mirror used by a dental surgeon is ..........................

Answer the following question:
Distinguish between the convex mirror and the concave mirror.

Name the mirror having a wider field of view.

Name the type of mirror having a focal length of +20 cm.

State three characteristics of the image formed by a convex mirror.

Write the sign convection used in optics.

Define the term Normal.

Draw a ray diagram to show that a convex mirror has a wider field of view.

A concave mirror can be used to produce a parallel beam of light. Draw a ray to illustrate this.

Which of the following has curved reflecting surface?

The distance from the pole to the focus is called

If the focal length of a spherical mirror is 10 cm, what is the value of its radius of curvature?

The spherical mirror used in a beauty parlour as make-up mirror is _______.

Geometric centre of the spherical mirror is ______.

Define focal length.

Numerical problem.

The radius of curvature of a spherical mirror is 25 cm. Find its focal length.

Assertion: Incident ray is directed towards the centre of curvature of spherical mirror. After reflection it retraces its path.

Reason: Angle of incidence (i) = Angle of reflection (r) = 0°

A student traces the path of a ray of light passing through a rectangular slab.

For measuring the angle of incidence, he must position the protractor in the manner shown in the figure:

An object is placed at a distance of 0.25 m
in front of a plane mirror. The distance between the object and image will be ______.

A shopkeeper wanted to fix a mirror that will give a maximum view of his shop. What type of mirror should he use? Give reason.

Spherical mirrors are one form of ______ mirrors.

The radius of curvature of a spherical mirror is 18 cm. What is the focal length of this mirror?

What is the difference between virtual images of an object formed by a concave mirror and a convex mirror?

A ray of light is incident towards a plane mirror at an angle of 30° with the mirror surface. What will be the angle of reflection?

For a spherical mirror, ______ is true.

A spherical mirror whose reflecting surface is curved outwards is called ______ mirror.

The image formed in a plane mirror is always inverted.

The minimum length of the mirror required to see the full image of the person is half ‘ of his height.

The distance from the center of curvature of the mirror to the pole is called the focal length of the mirror.

How tall does a mirror have to be to fit an entire person’s body?

Define the radius of curvature.

What is “aperture”?

In the figure shown, the image of a real object is formed at the point I. AB is the principal axis of the mirror. The mirror must be:

A converging lens of focal length f is placed at a distance 0.3 m from an object to produce an image on a screen 0.9 m from the lens. With the object and the screen in the same positions, an image of the object could also be produced on the screen by placing a converging lens of focal length.

In normal adjustment, for a refracting telescope, the distance between objective and eye piece is 30 cm. The focal length of the objective, when the angular magnification of the telescope is 2, will be ______.


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