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, , Board Question Paper: July 2020, , BOARD QUESTION PAPER: JULY 2020, Science and Technology Part - 1, Time: 2 Hours, Note: i., ii., iii., iv., v., , vi., Q.1. (A), i., , ii., , Total Marks: 40, , All questions are compulsory., Use of a calculator is not allowed., The numbers to the right of the questions indicate full marks., In case of MCQs (Q. No. 1(A)) only the first attempt will be evaluated and will be given credit., For each MCQ, the correct alternative (A), (B), (C) or (D) with sub-question number is to be written, as an answer., For Eg: (i) (A), (ii) (B), (iii) (C), Scientifically correct, labelled diagrams should be drawn wherever necessary., Choose the correct option:, The minimum velocity of the spacecraft to escape from earth’s gravitational force must be, _______., (A) 112 km/s (B) 11.2 km/s, (C) 1.12 km/s, (D) 0.112 km/s, The melting point of pure ethanoic acid is _______., (A) 17C, (B) 19C, (C) 15C, , (D), , [5], , 27C, , iii., , The process of separation of light into its component colour while it is passing through a, medium is called _______., (A) Reflection, (B) Refraction, (C) Dispersion, (D) Internal reflection, , iv., , The conversion of ferrous sulphate into ferric sulphate is _______ reaction., (A) Oxidation, (B) Displacement, (C) Electrolysis, (D) Reduction, , v., , Lithium (Li), _______ and Potassium (K) is Dobereiner’s triad., (A) Magnesium (Mg), (B) Aluminium (Al), (C) Sodium (Na), (D) Calcium (Ca), , (B), i., , Solve the following sub-questions:, State true or false:, The refractive index depends upon the velocity of light in medium., , ii., , Write the correlated answer:, Torch : Concave lens :: Camera : _______., , iii., , Find odd man out:, Zinc, Iron, Phosphorus, Sodium., , iv., , Draw the structural formula of C3H8., , v., , Which satellite is used in educational field among INSAT and GSAT series?, , [5], , Q.2. (A), i., ii., iii., , Give scientific reasons (any two):, Star appears to be twinkling at night., Simple microscope is used for watch repairs., The copper vessels turn greenish and silver articles turn blackish when kept open in air for, long time., , [4], , (B), i., , Answer the following questions (any three):, An object takes 5 seconds to reach the ground from a height of 5 m on a planet. What is the, value of ‘g’ on that planet?, , [6], , 1
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, , Std. X: Perfect Science and Technology Part - 1, ii., , Identify ‘A’ and ‘B’ from the following table and complete the table. Write the chemical, equation:, Limestone, Δ, , Heat, , …………., A, , …………., B, , iii., , Write the modern periodic law and also give the names of ‘blocks’ in modern periodic table., , iv., , Distinguish between ‘alternating current’ and ‘direct current’., , v., , Define specific heat capacity. Write its S.I. unit., , Q.3. Answer the following (any five):, i., An iron ball of mass 3 kg is released from a height of 125 m and falls freely to the ground., Assuming that the value of ‘g’ is 10 m/s2, calculate:, a., Time taken by the ball to reach the ground., b., Velocity of the ball on reaching the ground., ii., , An element has its electron configuration as (2, 8, 2). Answer the following:, a., What is the ‘atomic number’ of this element?, b., What is the ‘Group’ of this element?, c., To which period does this element belong?, , iii., , a., , Write the ‘endothermic’ or ‘exothermic’ nature of the reaction:, , 2KClO3 (s) , 2KCl(s) 3O2 , , b., , Balance the given chemical equation:, NaOH (aq) H 2SO 4(aq) Na 2SO 4 (aq) H 2 O (l), , c., , From given reaction, identify ‘oxidant’ and ‘reductant’:, , CuO H2 Cu H2O, iv., , A copper sphere of 100 g mass is heated to raise its temperature to 100C and is released in, water of mass 195 g and temperature 20C in a copper calorimeter. If the mass of the, calorimeter is 50 g, what will be the maximum temperature of water?, (Specific heat of copper = 0.1 cal/gC), , v., , a., b., c., , vi., , Complete the following table for convex lens:, , Draw a neat labelled diagram of ‘dispersion of white light through glass prism’., Which coloured ray is the least deviated?, Which coloured ray is the most deviated?, , Position of object, (a), (b), (c), , 22, , _______, , Position of image, At focus F2, , Size of image, Point image, , At 2F1, , At 2F2, , _______, , Between F1 and O, (within focal length), , On the same side (object, side), , Very large, , Nature of, image, Real and, inverted, Real and, inverted, _______, , [15]
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, , Board Question Paper: July 2020, vii., , Observe the following diagram and answer the questions:, Anode (Graphite), , Cathode, (Graphite lining), , Steel, tank, , Mixture of alumina,, cryolite and fluorspar, , Molten, aluminium, , a., b., c., , Outlet for molten, aluminium, , Write the ‘anode reaction’., Write the ‘cathode reaction’., What is the purpose of mixing ‘cryolite’ and ‘fluorspar’ with ‘alumina’ in the, electrolytic reduction of alumina?, , viii. a., b., c., , What is the principle behind the working of satellite launch vehicle?, Write the formula for the escape velocity., Write the long form of ‘ISRO’., , Q.4. Solve the following questions (any one):, i., Observe the diagrams and answer the questions:, +, , , , –, , S, , +, , Plug key, , B, , N, , (), , (), , W, , A, , [5], , A, , S, , N, , Plug key, , B, , E, Magnetic needle, , a., b., c., d., e., ii., , Magnetic needle, , Which effect of electric current is shown in the above figure?, What will happen if the number of electric cells is increased on the magnetic needle?, If the distance between the conductor and magnetic needle is increased, what will be, the effect on intensity of magnetic field?, If the ends of electric cell are interchanged, what will be the effect of the magnetic, needle?, Write the names of any two instruments which work on magnetic effect of electric, current., , Answer the following:, a., Draw the electron-dot structure of Methane., b., Define Homologous series., c., Write the IUPAC names of the following:, CH3 CH2 COOH, (i), (ii), (iii), , CH3 CHOH CH3, CH3 CO CH2 CH3, , 3
