Please wait...
1800-212-7858 (Toll Free)
9:00am - 8:00pm IST all days

or

Thanks, You will receive a call shortly.
Customer Support

You are very important to us

For any content/service related issues please contact on this toll free number

022-62211530

Mon to Sat - 11 AM to 8 PM

Ask Refraction By Lens question free ×

Queries asked on Sunday and after 7 pm from Monday to Saturday will be answered after 12 pm the next working day.

  • CBSE×
  • Class 12 Science×
  • Physics×
  • Ray Optics And Optical Instruments×
  • Refraction By Lens×

Refraction By Lens Free Doubts and Solutions

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

WHAT IS THE RAY DIAGRAM OF CONCAVE LENS WHEN OBJECT IS PLACED AT FOCUS?
PLEASE EXPLAIN IN DETAIL

Asked by modi72879 7th November 2017, 9:42 AM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

WHAT IS THE RAY DIAGRAM OF CONCAVE LENS WHEN OBJECT IS PLACED AT INFINITY?
PLEASE EXPLAIN IN DETAIL

Asked by modi72879 7th November 2017, 9:41 AM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

Ans with explanation 
 

Asked by Varsneya Srinivas 20th October 2017, 8:42 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

If the image formed in cinema is real then shouldn't it be inverted, and how do they avoid it?

Asked by nileshpatel19752000 13th October 2017, 11:52 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

Find power

Asked by bijuaylara111 8th September 2017, 12:15 AM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

what is the power and focal length of sunglasses?

Asked by vasturushi 7th September 2017, 10:42 AM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

How do we determine with which type of lens our spectacles are made?
According to the type of eye disordres how do the spectacle makers design them?

Asked by pksunilnair 26th April 2017, 10:22 AM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

briefly explain mathematically how the focal length of a concave lens will change when it is cut 
 
a) vertically   at the middle
b) horizontally at the middle

Asked by ppratim02 12th July 2016, 4:56 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

briefly explain  mathematically how the focal length of a  convex lens  will change when it is  cut  vertically at the middle

Asked by ppratim02 12th July 2016, 4:54 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

An equiconvex lens is cut into two identical plano convex lens. What is the ratio of focal lengths of equiconvex lens to that of plano convex lens...?
 

Asked by nayonikamenon15 11th January 2016, 12:33 AM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

draw a ray diagram to show the image formation in refraccting type astronomical telescope in the normal adjusment  when image is formed at infinity.derive an expression the aperture of objective lens and why?
 

Asked by mahamood.iphone 14th December 2015, 9:53 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

what will be the focal lenght of the lens if radii of curvature of two surfaces were equal in magnitude and also had the same sign?

Asked by Jahanvi 8th October 2015, 7:41 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

What is the relation between focal length and radius of curvature of a lens?Do the two focal lenghs of a lens  always have the same value?Are the focal lengths of a lens different for different medium?

Asked by joykphukan 21st July 2015, 9:13 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

The focal length of an equiconvex lens is equal to the radius of curvature of either face. What is the refractive index of the material of the lens? 

Asked by Topperlearning User 8th July 2015, 11:31 AM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

Q.56 The figure shows a convergent lens placed inside a cell filled with a liquid. The lens has a focal length +20 cm, when in air and its material has refractive index 1.5. if the liquid has a refractive index 1.6, the focal length of the system is
a) +80 cm
b) –80 cm
c) –24 cm
d) –160 cm

Asked by Malavika Umesh 5th May 2015, 6:16 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

an object is placed 12cm to the left of a converging lens of focal length 8cm.Another converging lens of 6cm focal length is placed at a distance of 30cm to the right of the first lens.Th e second lens will produce
a)no image
b)a virtual enlarged image
c)a real enlarged image
d)a real inverted image

Asked by Malavika Umesh 29th April 2015, 12:14 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

A thin plano-convex lens acts like a concave mirror of focal length 0.2m when silvered from its plane surface.THe refractive index of the material of the lens is 1.5. What will be The radius of curvature of the convex surface of the lens??

Asked by Malavika Umesh 26th April 2015, 10:46 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

Q.On a convex lens ,light of red and violet colour is incident separately , then how does the focal length of lens change?

Asked by Ravi consul 4th March 2015, 6:48 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

A convex lens of focal length 20cm and made of glass of refractive index 1.5 is immersed in water of reffractive index 1.33 calculate change in focal length of the lens 

Asked by Sandeep Yadav 6th December 2014, 11:09 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

Calculate the distance d show that areal imageof an object at O 15cm is front of a convex lens of focal length 10cm we formed at asame point othe radius of curvature of the mirror is 20cmwill the image inverted and erect .

Asked by Sandeep Yadav 4th December 2014, 8:47 AM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

A concave lens of glass, refractive index 1.5, has both surface of the same radius of curvature R. On immersion in a medium of refractive index 1.75, it will

Asked by yashu.fly 22nd November 2014, 10:18 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

can u plzz explain the difference of  sign conventions in  the cases  of reflection and refraction in both concave and convex lense as well as mirrors  also diffrence of sign convention in case of magnfication. it is not clear to through notes .kindly answer this question as quikly as possible ..........

Asked by NAVYA SOOD 19th July 2014, 8:57 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

Draw a ray diagram to show the formation of real image of the same size as that of the object placed in front of a converging lens. Using this ray diagram establish the relation between u, v and f for this lens.

OR

Derive the lens formula Syntax error from line 1 column 49 to line 1 column 73. Unexpected '<mstyle '.for a concave lens, using the necessary ray diagram.

Asked by Topperlearning User 8th July 2014, 1:39 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

There are n number of lenses of focal length f 1 , f 2 ,....fn in contact. What is the focal length and the power of the combination.

Asked by Topperlearning User 10th June 2014, 9:48 AM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

A convex lens has a focal length of 30cm. An object is placed at a distance of 20cm from the lens. What is the nature of image formed by refraction at lens?

Asked by Topperlearning User 10th June 2014, 9:45 AM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

A convex lens Syntax error from line 1 column 49 to line 1 column 73. Unexpected '<mstyle '. behaves as converging lens when dipped in water Syntax error from line 1 column 49 to line 1 column 73. Unexpected '<mstyle '. whereas it behaves as diverging lens when dipped in carbon disulphide Syntax error from line 1 column 49 to line 1 column 73. Unexpected '<mstyle '.. Why?

Asked by Topperlearning User 10th June 2014, 9:28 AM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

Glass of refractive index 1.55 is used to manufacture a double convex lens with the same radii of curvature R. For the focal length of lens to be 25 cm, what is the radius of curvature?

Asked by Topperlearning User 10th June 2014, 9:16 AM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

A pin placed 40 cm from a lens forms an image on a screen placed at 80 cm on the other side of the lens. Determine the type of lens, focal length of lens.

Asked by Topperlearning User 10th June 2014, 8:58 AM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

There is a convex air bubble in a tank of water. State its behavior as a lens.

Asked by Topperlearning User 10th June 2014, 8:55 AM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

Two lenses of power 10 D and -5 D are placed in contact. (i) Calculate the power of lens combination. (ii) Where should an object be held from the lens, so as to obtain a virtual image of magnification 2 ?

Asked by Topperlearning User 10th June 2014, 7:52 AM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

The image of an object formed by a lens on the screen is not in sharp focus. Suggest a method to get clear focussing of the image on the screen without disturbing the position of the object, the lens or the screen.

Asked by Topperlearning User 10th June 2014, 7:20 AM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

A convex lens of refractive index 1.5 has a focal length of 18 cm in air. Calculate the change in its focal length when it is immersed in water of refractive index .

Asked by Topperlearning User 4th June 2014, 1:23 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

A convex lens made up of glass of refractive index 1.5 is dipped, in turn, in: (i) Medium A of refractive index 1.65 (ii) Medium B of refractive index 1.33 Explain, giving reasons, whether it will behave as a converging lens or a diverging lens in each of these two media.

Asked by Topperlearning User 4th June 2014, 1:23 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

A convex lens of focal length 30 cm is placed coaxially in contact with a concave lens of focal length 40 cm. Determine the power of the combination. Will the system be converging or diverging in nature?

Asked by Topperlearning User 4th June 2014, 1:23 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

The radii of curvature of the faces of a double convex lens are 10 cm and 15 cm. If focal length of the lens is 12 cm, find the refractive index of the material of the lens.

Asked by Topperlearning User 4th June 2014, 1:23 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

Violet light is incident on a thin convex lens. If this light is replaced by red light , explain with reason, how the power of the lens would change ?

Asked by Topperlearning User 4th June 2014, 1:23 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

Two thin lenses of focal length 5 cm and 10 cm are placed in contact. What will be the focal length of the combination?

Asked by Topperlearning User 4th June 2014, 1:23 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

A combination of two thin lenses has a power of +10D. If one of the concave lens has a focal length 1/4m. Find the nature and power of other lens.

Asked by Topperlearning User 4th June 2014, 1:23 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

The power of a lens is (i) +6D and (ii) -2D what is the focal length and nature of lens?

Asked by Topperlearning User 4th June 2014, 1:23 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

A lens has a focal length of -30cm. What is the nature and power of the lens?

Asked by Topperlearning User 4th June 2014, 1:23 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

State the conditions under which the concave lens behave as a converging lens.

Asked by Topperlearning User 4th June 2014, 1:23 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

Suppose a lens has different radii of curvature, it forms an image of an object placed on its axis. If we reverse the lens will the position of the image of the object change?

Asked by Topperlearning User 4th June 2014, 1:23 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

The refractive index of concave lens is 1.2. This lens is immersed in a liquid of refractive index 1.4. Explain the behavior of the lens.

Asked by Topperlearning User 4th June 2014, 1:23 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

The image of a small electric bulb fixed on wall of a room is to be obtained on opposite wall of a room 3m away by means of large convex lens. What is the maximum possible focal length of the lens required for this purpose?

Asked by Sourav Naval 1st June 2014, 1:53 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

Write thin lens formula for a convex lens and draw the graph showing the variation of u and v for a convex lens.

Asked by Topperlearning User 22nd May 2014, 3:29 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

Calculate the focal length of the combination o f a convex lens of focal length 30 cm in contact with a concave lens of focal length 20 cm. Is the system a converging or a diverging lens ?

Asked by Topperlearning User 22nd May 2014, 2:05 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

What is the magnification if n number of lenses are used to magnify an object?

Asked by Topperlearning User 22nd May 2014, 1:25 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

What is dioptre?

Asked by Topperlearning User 22nd May 2014, 1:20 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

Why do we combine two or more lenses?

Asked by Topperlearning User 22nd May 2014, 1:18 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

Focal length of a convex lens is 25cm. Calculate the power of the lens?

Asked by Topperlearning User 22nd May 2014, 12:59 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

A +4D glass lens is immersed in water completely. What will be the effect on lens's power?

Asked by Topperlearning User 22nd May 2014, 12:56 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

Radius of curvature of a plano-convex lens of glass () is 25 cm. What is the focal length?

Asked by Topperlearning User 22nd May 2014, 9:57 AM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

CBSE - XII Science - Physics - Ray Optics and Optical Instruments

explain and derive lens makers formula.

Asked by Sagar krishna 16th May 2014, 6:39 PM
Answered by Expert

Answer this question

×
Your answer has been posted successfully!

Latest Questions

Chat with us on WhatsApp