# Free Class 10 Science Chapter 7 Lenses questions answers

We offer free Maharashtra Board Class 10 Science Chapter 7 Lenses questions answers in Pdf format. Our expert team have gone through this chapter and prepared Notes for the students who are facing difficulties in summarizing of this chapter. We assure you that you can score more marks by using our Pdf files. Let us tell you that all the questions answers in concern with this chapter are prepared by our expert teachers team. Here you will find three Pdf files, among them first Pdf files consists of Textbook Questions Answers whereas in second Pdf files you will get the additional extra questions for practices. In the third and last Pdf files, you will get full exercise of this chapter.

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## Class 10 Science Chapter 7 Lensesquestions answers in Pdf format:

Here is what you all are waiting for. Teachers, parents and student, now you will find below the Solutions of Class 10 Science Chapter 7 Lenses questions answersFrom the subject English of Maharashtra State Board.

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## Class 10 Science Chapter 7 Lenses: Notes

As we go through the entire Class 10 Science Chapter 6 Refraction of Light, we can see there are so many questions asked meanwhile and students are expected to answers them. Some students may face some problem while answering it , but we promise you that after reviewing our answer, you will gain the confidence to answers such questions. Our expert team teacher have divided the solutions into several parts,which will help you to understand this chapter better. Have a look at the following parts:

• Refraction of Light (Can you recall?)
• Refraction of Light (Use your brain power)
• Refraction of Light (Observe/Discuss:)
• Refraction of Light (Let’s Discuss:)
• Refraction of Light (Observe:)
• Refraction of Light (Let’s think:)
• Refraction of Light (Paragraph based questions:)
• Refraction of Light (Questions based on tables and charts:)
• Refraction of Light (Activity based questions:)
• Refraction of Light (Projects:)

## Class 10 Science Chapter 7 Lenses: Question Bank

All those students who are preparing for the final exam and want to score more marks on board can refer to our question bank, among them are some questions may ask you in your final examination.

Beneath, in our Pdf documents, you get the Class 10 Science Chapter 7 Lenses questions answers, however our expert crew have faith in the query bank that allows you to help the students to get more marks.
Our expert team of teachers has prepared the best solutions to these questions. All the answers to these questions are given in our PDF file, which is given below. You can download it for your later study. In Our Pdf file of solutions of the Chapter 7 Lenses, you will find the solutions of Important Question bank given below.

#### Important Questions Bank

Fill in the blanks and rewrite the statements:

Question 1. The focal length of a………..lens is positive.
Question 2. The focal length of a………..lens is negative.
Question 3. The magnification produced by a………..lens is always positive.
Question 4. The power of a………..lens is positive.
Question 5. The power of a………..lens is negative.
Question 6. The focal length of a lens with power 2.5 D is………..
Question 7. The power of a lens with focal length 20 cm is………..
Question 8. The minimum distance of distinct vision for a normal human eye is………..
Question 9. If two lenses with focal lengths 10 cm and 20 cm respectively are kept in contact with each other, the effective power of the combination is………..
Question 10. A………..lens is used as a simple microscope.

Rewrite the following statements by selecting the correct options:
Question 1. Inside water, an air bubble behaves………..
(a) like a flat plate
(b) like a concave lens
(c) like a convex lens
(d) like a concave mirror

Question 2. …………represents the lens formula.

Question 3. The power of a convex lens of focal length 25 cm is………..
(a) +4.0 D
(b) 0.25 D
(c) -4.0 D
(d) -0.4D

Question 4. A lens does not produce any deviation of a ray of light passing through………..
(a) it’s centre of curvature
(b) it’s optical centre
(c) it’s principal focus
(d) an axial point at a distance 2F from its centre

Question 5. The image formed by a concave lens is always………..
(a) virtual and erect
(b) real and erect
(c) virtual and inverted
(d) real and inverted

Question 6. A convex lens forms a virtual image of an object placed………..
(a) at infinity
(b) at a distance 2F from the lens
(c) at a distance F from the lens
(d) between the principal focus and the optical centre of the lens.

Question 7. When an object is placed at 2F1 of a convex lens, its image is formed………..
(a) at F1
(b) at 2F2
(c) beyond 2F2
(d) on the same side as the object

Question 8. To obtain an image of the same size as that of an object with the help of a convex lens, the object should be placed………..
(a) at infinity
(b) beyond F1
(c) between F1 and 2F1
(d) at 2F1

Question 9. When an object is placed between O and F1 in front of a convex lens, the image formed is ………..
(a) enlarged and erect
(b) diminished and erect
(c) real and enlarged
(d) diminished and inverted

Question 10. When an object is placed at any finite distance from a concave lens, the image is formed ………..
(a) between F1 and 2F1
(b) beyond 2F1
(c) at F1
(d) between F1 and O on the same side as the object.

Question 11. A student obtained a clear image of window grills on the screen. But the teacher told him to get the image of a tree far away, instead of the window. To get a clear image, the lens must be ……….. (Practice Activity Sheet – 2)
(a) moved towards the screen
(b) moved away from the screen
(c) moved behind the screen
(d) moved far away from the screen

Question 12. The image obtained while finding the focal length of a convex lens is ……….. (Practice Activity Sheet – 3)
(a) real and erect
(b) virtual and erect
(c) real and inverted
(d) virtual and inverted

Question 13. Yash found out f1 and f2 of a symmetric convex lens experimentally. Then which of the following conclusions is true? (Practice Activity Sheet – 4)
(a) f1 = f2
(b) f1 > f2
(c) f1 < f2
(d) f1 ≠ f2

State whether the following statements are true or false: (If a statement is false, correct it and rewrite it.)

Group (A)
Question 1. Power of a lens, P = $$\frac{1}{f}$$.
Question 2. If the power of a lens is 2 D, its focal length = 0.5 m.
Question 3. A concave lens is a converging lens. (March 2019)
Question 4. A convex lens is a diverging lens.
Question 5. A concave lens always forms a virtual image.
Question 6. A convex lens always forms a virtual image.
Question 7. Due to the light sensitive cells in the eye, we get information about the brightness or dimness of the object and the colour of the object.
Question 8. The focal length of a concave lens is negative.
Question 9. The magnification produced by a concave lens is positive or negative depending on the object distance.
Question 10. The magnification produced by a convex lens is positive or negative depending on the object distance.
Question 11. A concave lens is used as a magnifying glass.
Question 12. A convex lens is used as a simple microscope.
Question 13. A concave lens is used to correct myopia.
Question 14. A convex lens is used to correct hypermetropia.

Group (B)
Question 1. When red light falls on the eyes, the cells responding to red light get excited more than those responding to other colours and we get the sensation of red colour.
Question 2. When an object is placed in front of a concave lens, its image is obtained on the opposite side of the object.
Question 3. The image formed by a concave lens is always virtual.
Question 4. The principal focus of a convex lens is virtual.
Question 5. An object of height 2 cm forms an image of height 3 cm when placed in front of a concave lens.
Question 6. Absence of rod like cells results in colour blindness.
Question 7. Nearsightedness can be corrected using spectacles having convex lenses.
Question 8. Farsightedness can be corrected using spectacles having convex lenses of suitable focal length.
Question 9. As one grows old, ciliary muscles become weak.
Question 10. In a simple microscope, the object is placed within the focal length of the convex lens.
Question 11. A compound microscope forms an erect and real image of a small object.
Question 12. In a compound microscope, a real image acts as an object for the eyepiece.
Question 13. In television, we see a continuous picture due to persistence of vision.
Question 14. The conical cells can respond differently to red, green and blue colours.
Question 15. The rod like cells respond to colours and communicate the presence of colours in the retinal image of the brain.
Question 16. The conical cells respond to the intensity of light and communicate the degree of brightness and darkness to the brain.
Question 17. Generally, using the same objective lens, but different eyepieces, different magnification can be obtained.

Find the odd one out and give the reason:
Question 1. Simple microscope, Compound microscope, Telescope, Myopia.
Question 2. Myopia, Presbyopia, Hypermetropia, Spectrometer.
Question 3. Presbyopia, Retina, Nearsightedness, Farsightedness.
Question 4. Compound microscope, Kaleidoscope, Simple microscope, Astronomical telescope.
Question 5. TV, Motion picture, Complete circle formed by a revolving burning incense stick, Colour blindness.
Question 6. Planets, Stars, Satellites, Rainbow.

Considering the correlation between the words of the first pair, pair the third word accordingly with proper answer:
Question 1. Nearsightedness: Elongated eyeball :: Farsightedness:………
Question 2. Convex lens : Converging :: Concave lens :………..
Question 3. Object at 2F1 of a convex lens : Image at 2F2 :: Object at F1 :………..
Question 4. Magnification positive : Erect image :: Magnification negative :………..
Question 5. Convex lens : Positive power of the lens :: Concave lens:
Question 6. $$\frac{1}{f(\text { in metre })}$$ : Power of the lens (in dioptre) :: $$\frac{\text { Image distance }}{\text { Object distance }}$$
Question 7. Focal length : Metre :: Power of a lens :………..
Question 8. Iris : Pupil :: Ciliary muscles :……….
Question 9. Nearsightedness : Concave lens :: Farsightedness :………..
Question 10. Nearsightedness : Image in front of the retina :: Farsightedness :………..
Question 11. Observation of stars and planets : Telescope :: Repairing a watch :……….
Question 12. Cinema : Persistence of vision :: Rainbow :………