physics-IP Jai maurya.pptx class 12 investigatory project for baords

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1. This is certified that Ma. AJAY KUMAR PRAJAPATI has completed the project titled – “ To find refractive indices of water and turpentine oil using a plane mirror , a equiconvex lens (made from a glass of known refractive index) and an adjustable object needle ” with sincerely and obedience . He is obedient and hard working . I hereby declare that he is well behaved to the best of my knowledge . This project may be considered as fulfillment for AISSCE conducted by CBSE Board. MISS.HUMA PARVEEN EXTERNAL PRINCIPAL (HEAD OF PHYSICS DEPT.) JNV CHURHAT

2. I wish to express my deep gratitude and sincere thanks to the Principal Mrs. Beena Bhattacharya , Jawahar Navodaya Vidyalaya Churhat Distt. Sidhi (M.P.) for her encouragement and for all the facilities that she provides for this project work. I sincerely appreciate this magnanimity by taking me into her fold for which I shall remain indebted to her . I extend my heartily thanks to Miss. Huma Parveen , Physics Teacher , who guided me to the successful completion of this project. I can’t forget to offer my sincere thanks to Laboratory Attendent Mr.R.P. Kori & also to my classmate who helped me to carry out this project work suscessfully & for their valuable advice and support , which I received from them time to time .

3. I do hereby declare that this project work has been originally carried under the guidance and supervision of Miss. Huma Parveen , Head of Physics Department , Jawahar Navodaya Vidyalaya Churhat , Distt . Sidhi (M.P.) Student’s Name :- AJAY KUMAR PARAJAPATI JAWAHAR NAVODAYA VIDYALAYA CHURHAT DISTT.SIDHI (M.P.)

4. AIM APPARATUS THEORY PROCEDURE DIAGRAMS OBSERVATION CALCULATIONS RESULT PRECAUTIONS SOURCE OF ERROR

5. “ To find refractive indices of water and turpentine oil using a plane mirror, a equiconvex lens (made from a glass of known refractive index) and an adjustable object needle ”

6. FOR FINDING THE FOCAL LENGTH OF CONVEX LENS:- Measure the rough focal length of convex lens place the plane mirror with the convex lens placed on it above the horizontal base of a clamp stand horizontally as its tip lies vertically above the optical centre of the lens. Adjust the needle at a height a little more than the rough focal length of the concave lens. Try to remove the parallax between the tip of the object needle and its image tip. Note the distance of tip of the needle from the centre of the upper surface of the lens. Let it be X 1 (use plumb line ) Remove the convex lens and measure the distance of the tip of the needle from the plane mirror. Let it be X 2 (use plumb line) Repeat and record all the observations.

7. Pitch of the spherometre = 1cm Least count of the spherometre = 0.01cm Distance between the legs :- AB = 3cm BC = 3cm CA = 3cm Table for calculation of ‘h’ S.NO. Initial reading of the C.S. on the convex lens (a) No. of complete rotations Final readings of the C.S on the glass slab Additional C.S div. Moved h = n × pitch + m × L.C Mean “h” 1 62 6.5 55.5 0.555 0.5775 2 64 4 60 0.6

8. Area between lens and plane mirror S.no . Tip of the upper surface of the concave lens X 1 Upper surface of the plane mirror X 2 Mean X = X 1+ X 2 / 2 Focal length Without liquid 1 30.5 31 30.75 f1 = 33.85 2 367 37.2 36.95 With water 1 31.4 31.8 31.6 f2 = 34.7 2 375 38.1 37.8 With oil 1 9.4 9.6 9.5 f3 = 10 2 10.4 10.6 10.5 Distance of needle tip from To measure focal length ‘f’ of convex lens

9. The screw of the spherometer should be moved in one direction only to avoid backlash error. The screw should be moved just to touch the surface of the convex lens or the glass slab. The parallax should be removed properly. The lens and plane mirror should be properly cleaned. The convex lens of large focal length should be used. The spherometre reading should be taken first on the surface of the convex lens and then on the glass slab.

10. The distance ‘X 1 ’ and ‘X 2 ’ may not be measured correctly. The value of ‘h’ and ‘I’ may not be correct. Parallax may not be removed properly. Backlash error may be acting on the spherometer .