Std. XI Science Physics Practical Handbook

Transcription

1 Std. XI Science Physics Practical Handbook

2 No. Experiments Page No. 1 Use of Vernier Callipers 1 2 Use of Micrometer screw gauge 5 3 Use of Spherometer 9 4 Parallelogram law of forces 12 5 Coefficient of static friction 15 6 Determination of Resistance per cm by V I graph 2 7 Concave Mirror 24 8 Convex Lens 26 9 Convex Mirror 29 1 Focal length of concave lens by convex lens Prism Use of Travelling Microscope 4 13 I Refractive index of liquid by concave mirror II Refractive index of liquid by convex lens & plane mirror I Specific heat capacity of liquid II Specific heat capacity of solid List of Activity 51 Logarithms and other tables Logarithms 56 Antilogarithms 58 Natural Sines 6 Natural Cosines 62 Natural Tangents 64

3 Std. XI Sci. Physics Practical Handbook Prof. Jyoti D. Deshpande M.Sc., D.H.E. H.O.D., Ramniranjan Jhunjhunwala College, Ghatkopar Target PUBLICATIONS PVT. LTD. Mumbai, Maharashtra Tel: Website: mail@targetpublications.in

4 Std. XI Sci. Physics Practical Handbook (New Syllabus) Target Publications Pvt Ltd. Second Edition: June 212 Price: ` 45/- Printed at: India Printing Works 42, G.D. Ambekar Marg, Wadala, Mumbai 4 31 Published by Target PUBLICATIONS PVT. LTD. Shiv Mandir Sabagriha, Mhatre Nagar, Near LIC Colony, Mithagar Road, Mulund (E), Mumbai Off.Tel: mail@targetpublications.in

5 PREFACE Physics has played a major role in the development of science and technology during the years. It covers a wide range of phenomena, from the smallest sub-atomic particles to the largest galaxies. It is the study of matter and energy and the interaction between them. Practical physics has applications in the fields of engineering, medicine, technology etc. In practical physics the student obtain laboratory skills, design experiments and apply instrumentation such as electronic circuits to observe and measure natural phenomena. To master the science of physics practical one needs to have a complete and thorough knowledge of all the experiments involved. Hence we bring to you Std. XI Sci. : PHYSICS PRACTICAL HANDBOOK which covers all the experiments of Std XI. This handbook is writtern according to the syllabus. It includes different sets of experiments with proper steps and neat and labelled diagrams. These experiments help the student to understand the practical applications of many principles and laws involved in Std. XI. The handbook also includes all the useful tables given at the end. And lastly, we would like to thank all those who have helped us in preparing this book. There is always room for improvement and hence we welcome all suggestions and regret any errors that may have occurred in the making of this book. A book affects eternity; one can never tell where its influence stops. Best of luck to all the aspirants! Your s faithfully Publisher

6 Syllabus SYLLABUS 1. Use of Vernier Callipers. 2. Use of Screw gauge. 3. To determine radius of curvature of a given spherical surface by a spherometer. 4. To find the weight of a given body using parallelogram law of vectors. 5. To study the relationship between force of limiting friction and normal reaction and to find coefficient of friction between a block and horizontal surface. 6. To determine resistance per cm of a given wire by plotting a graph of potential difference versus current. 7. To find the value of v for different values of u in case of a concave mirror and to find the focal length. 8. To find the focal length of a convex lens by plotting graphs between u and v or between 1/u and 1/v. 9. To find the focal length of a convex mirror, using a convex lens. 1. To find the focal length of a concave lens, using a convex lens. 11. To determine angle of minimum deviation for a given prism by plotting a graph between angle of incidence and angle of deviation. 12. To determine refractive index of a glass using a travelling microscope. 13. To find refractive index of a liquid by using (i) concave mirror, (ii) convex lens and plane mirror. 14. To determine specific heat capacity of a given (i) liquid (ii) solid, by method of mixtures. List of Activities 1. To make a paper scale of given least count, e.g..2 cm,.5 cm. 2. To determine mass of a given body using a meter scale by principle of moments. 3. To plot a graph for a given set of data, with proper choice of scales and error bars. 4. To measure the force of limiting friction for rolling of a roller on horizontal plane. 5. To study the variation in range of a jet of water with angle of projection. 6. To measure resistance, voltage (AC/DC), current (AC) and check continuity of a given circuit using multimeter. 7. To observe refraction and lateral deviation of a beam of light incident obliquely on a glass slab. 8. To study the nature and size of image formed by (i) convex lens (ii) concave mirror, on a screen by using a candle and a screen (for different distances of the candle from the lens/mirror). 9. To obatin a lens combination with the specified focal length by using two lenses from the given set of lenses. 1. To note the change in level of liquid in a container on heating and interpret the observations. Std. XI Sc.: Physics Practical Handbook

7 General Instructions GENERAL INSTRUCTIONS 1. Before performing the experiment read the experiment at home carefully and take out the points on which you want the clarification from the teacher. 2. Before actually performing an experiment student should know clearly what do determine and by which method. 3. The necessary theory to know the limitations of the method and approximations used in formula should be read. 4. The working table must be clean and apparatus should be placed in such a manner that the part which are to be read or adjusted lie at convenient distance to make the observations. 5. The apparatus must be handled with great care. 6. Read all the precautions before performing the experiment. 7. Before writing down any final observation, take some trial readings and find out the range you are going to cover. Divide the range into equal parts according to the number of readings you are going to take. 8. Since all the measurements are affected by errors of observations repeat your observations at least three times for the same quantity and take the mean value. Sometimes it happens that one of the observed values differs widely from the rest. Reject that value. 9. The proper units to the measured quantity, should be written. 1. Writing of observations on loose sheets should be strictly avoided. The observations should be recorded in the practical note book. There should be no over writing. 11. Always bring compass box, sharpened pencil, eraser, hand book in the Laboratory. 12. Calculations for all observations neatly and with the help of logarithmic tables. Write the result with the proper units. Std. XI Sc.: Physics Practical Handbook

8 Use of Vernier Callipers 1 USE OF VERNIER CALLIPERS EXPERIMENT Aim: i. To find the volume of a sphere and ii. To find volume of a hollow cylinder, by using vernier callipers. Apparatus: Vernier callipers, sphere, hollow cylinder. Diagram: P Q Main Scale P Q Vernier scale Sphere/Cylinder Vernier callipers Diagram Main Scale Vernier scale (a) No zero error Main scale 5 Vernier scale Diagram cm (b) Negative zero error Main scale 5 Vernier scale 1 1 cm Diagram - 3 Std. XI Sci. : Physics Practical Handbook 1

9 Use of Vernier Callipers Main scale 1 cm Formula: (c) Positive zero error 5 Vernier scale Diagram i. Volume of a sphere = ii. 4 r 3 3 π Where r is radius of sphere Volume of cylinder = πr 2 h Where R is radius of cylinder and h is height of cylinder. Procedure: i. Note down the value of one division of main scale (X) and number of divisions on vernier scale (N). Hence find out least count of vernier callipers (See diagram - 1). ii. Find zero error of vernier callipers (See diagrams 2, 3, 4). iii. To measure the diameter and hence radius of sphere, place the given sphere between the two jaws of the vernier callipers. Care should be taken that undue pressure on the sphere is iv. avoided. Observe the zero of the vernier scale. It lies between two successive readings of the main scale. The lesser reading is the main scale reading (M.S.R.) a v. Now count the division of vernier scale which coincides with any of the division of main scale. This coinciding division of vernier scale is vernier scale division (V.S.D.) n. Multiply n by least count of vernier callipers to obtain the value of vernier scale reading. This is b and it is b = n least count. vi. The total reading is the sum of main scale reading a and vernier scale reading b. This total reading gives the diameter of the sphere. vii. Repeat the procedure (iv) to (vi) five times by rotating the sphere to get diameter at different places. Hence mean diameter and radius can be found out. viii. Place the cylinder between the two jaws of the vernier callipers. Repeat the procedure (iv) to (vii). Find out inner diameter and hence radius of the cylinder. ix. Measure the height of the cylinder by meter scale. x. Apply zero correction due to zero error for every reading. Observations: i. Value of the smallest division on main scale (X) =.. cm ii. Number of divisions on vernier scale (N) = div Least count of vernier callipers, L.C. = X N =. iii. Height of the cylinder =. cm Std. XI Sci. : Physics Practical Handbook 2

10 Use of Vernier Callipers Observation table: Object Obs. No. M.S.R. a V.S.D. n (div.) V.S.R. b = n L.C. Total reading (a + b) Corrected reading Sphere Cylinder Calculations: i. Corrected mean diameter of sphere = d =. cm Radius of sphere = r = d 2 =. cm ii. Corrected mean inner diameter of cylinder = D =. cm Radius of cylinder = R = D 2 =. cm iii. Volume of sphere = V = 4 3 π r3 = cm 3 iv. Volume of cylinder = V = π R 2 h = cm 3 Result: i. Volume of sphere =.. cm 3 ii. Volume of cylinder =.. cm 3 Std. XI Sci. : Physics Practical Handbook 3

11 Use of Vernier Callipers Precautions: i. While holding object in the jaws, do not exert undue pressure on it. The jaws should just touch the object. ii. Take number of readings at different positions of the sphere as well as cylinder. iii. The upper jaws should just touch the inner diameter of hollow cylinder. iv. The coinciding division of vernier scale should be taken accurately, if required magnifying glass can be used. Space for calculation: Std. XI Sci. : Physics Practical Handbook 4

12 2 Use of Micrometer screw gauge USE OF MICROMETER SCREW GAUGE EXPERIMENT Aim: i. To measure the diameter of a wire by using micrometer screw gauge. ii. To measure the thickness of a metal glass plate by using micrometer screw gauge. Apparatus: Micrometer screw gauge, wire and metal plate or glass plate etc. Diagram: Projecting cylindrical metal piece (Anvil) Circular Scale Main Scale Nut Sleeve Thimble Object Spindle Reference line Ratchet U-Shaped metal frame Diagram - 1 Reference line Diagram - 2 No zero error Reference line Diagram Negative zero error Reference line Diagram Positive zero error Std. XI Sci. : Physics Practical Handbook 5

13 Formula: Cross-sectional area of wire A = πr 2 Where r = radius of cross section of wire. Use of Micrometer screw gauge Procedure: i. Find out the distance (X) through which screw travels on the main scale in five rotations of the circular scale. Hence distance travelled by the circular scale in one rotation is called the pitch of the screw. ii. Note down the number of divisions on the circular scale. Hence knowing pitch, L.C. (Least count) of the screw can be determined (See diagram - 1). iii. Find out zero error of micrometer screw. This can be found out as follows: When the two jaws of micrometer screw gauge are brought in contact with each other without applying undue pressure, the zero on the circular scale should coincide with the reference line on main scale. If this happens there is no zero error (See diagram - 2). If this is not observed then the micrometer screw has zero error. There are two possibilities a. Zero of circular scale is above the reference line: When zero of the circular scale is above the reference line as shown in diagram - 3, then zero error is negative. Count the divisions from zero of circular scale coinciding with reference line ( m). Negative sign is for negative error. The value of zero error can be found out by multiplying it by least count. [( m) L.C.] b. Zero of circular scale is below the reference line: When zero of the circular scale is below the reference line as shown in diagram - 4, then zero error is positive. The division of circular scale coinciding with reference line is noted (+m). Positive sign is for positive error. The value of zero error can be found out by multiplying it by least count. [+(m) L.C.] Note that any micrometer screw gauge apparatus can have one and only one possibility out of the three i.e. no zero error, negative zero error and positive zero error. Also zero error is related to the apparatus. iv. Hold the wire, between the two jaws of micrometer screw gauge, whose diameter is to be found out without applying undue pressure. Note down the reading of the main scale (M.S.R.) or pitch scale (P.S.R.). This is a. v. Note down the circular scale reading coinciding with reference line. This is C.S.D. (n). Multiply this by L.C. to obtain circular scale reading (C.S.R.). vi. The total reading (T) can be found out by adding main scale reading and circular scale reading i.e. T = a + b. vii. To obtain correct reading, zero error which is found out in procedure (iii) is subtracted from total reading. Thus correct reading of the diameter is obtained. viii. Five readings of the diameter of the wire are taken by using procedure (iv) to (vii). Hence mean corrected diameter of the wire can be found out. ix. To find the thickness of the metal plate (or glass plate) instead of the wire, glass or metal plate is held between the jaws of the micrometer screw gauge. The procedure (iv) to (viii) is repeated, resulting in mean thickness of the plate (metal or glass). Std. XI Sci. : Physics Practical Handbook 6

14 Observations: i. Distance (X) travelled by the circular scale in five rotations =. cm Use of Micrometer screw gauge ii. Pitch of the screw = X 5 =.. iii. Number of divisions on the circular scale =.. iv. Pitch L.C. = No. of divisions on circular scale = v. Zero error, Z = ± (m) (L.C.) = Observation table: Object Obs. No M.S.R. a C.S.D. n (div.) C.S.R. b = n (L.C.) Total reading T = a + b Corrected reading = T Z Wire Plate Note: From the diameter of wire, radius of the wire can also be found out and hence cross sectional area of the wire can be calculated. From the last column in the observation, mean diameter of the wire and mean thickness of the plate can be found out. Result: i. Diameter of wire =. cm ii. Thickness of the plate (metal or glass) =. cm Std. XI Sci. : Physics Practical Handbook 7

15 Use of Micrometer screw gauge Precautions: i. Do not apply undue pressure while turning micrometer screw. ii. Take number of independent readings by holding the wire in different positions. iii. Minimise the blacklash error by rotating the screw always in the same direction while taking readings. Space for calculation: Std. XI Sci. : Physics Practical Handbook 8