[ { "section": "A", "question_number": "1(i)", "answer": "b", "marks": 1 }, { "section": "A", "question_number": "1(ii)", "answer": "a", "marks": 1 }, { "section": "A", "question_number": "1(iii)", "answer": "c", "marks": 1 }, { "section": "A", "question_number": "1(iv)", "answer": "a", "marks": 1 }, { "section": "A", "question_number": "1(v)", "answer": "b", "marks": 1 }, { "section": "A", "question_number": "1(vi)", "answer": "c", "marks": 1 }, { "section": "A", "question_number": "1(vii)", "answer": "d", "marks": 1 }, { "section": "A", "question_number": "1(viii)", "answer": "b", "marks": 1 }, { "section": "A", "question_number": "1(ix)", "answer": "a", "marks": 1 }, { "section": "A", "question_number": "1(x)", "answer": "a", "marks": 1 }, { "section": "A", "question_number": "1(xi)", "answer": "b", "marks": 1 }, { "section": "A", "question_number": "1(xii)", "answer": "a", "marks": 1 }, { "section": "A", "question_number": "1(xiii)", "answer": "c", "marks": 1 }, { "section": "A", "question_number": "1(xiv)", "answer": "d", "marks": 1 }, { "section": "A", "question_number": "1(xv)", "answer": "a", "marks": 1 }, { "section": "A", "question_number": "2(i)(a)", "answer": "C¹⁴ is a radioisotope because of the instability of the nucleus. Used for carbon dating.", "marks": 2 }, { "section": "A", "question_number": "2(i)(b)", "answer": "Class II lever.", "marks": 1 }, { "section": "A", "question_number": "2(ii)(a)", "answer": "Centripetal", "marks": 1 }, { "section": "A", "question_number": "2(ii)(b)", "answer": "zero", "marks": 1 }, { "section": "A", "question_number": "2(iii)", "answer": "30 N", "marks": 2 }, { "section": "A", "question_number": "2(iv)(a)", "answer": "Mechanical advantage using a block and tackle system of 9 pulleys is 9 whereas the mechanical advantage of a single moveable pulley is 2.", "marks": 1 }, { "section": "A", "question_number": "2(iv)(b)", "answer": "Increase of number of pulley increases mechanical advantage.", "marks": 1 }, { "section": "A", "question_number": "2(v)", "answer": "4:1", "marks": 2 }, { "section": "A", "question_number": "2(vi)(a)", "answer": "Resistance decreases", "marks": 1 }, { "section": "A", "question_number": "2(vi)(b)", "answer": "Current (Intensity of light) increases as resistance decreases", "marks": 1 }, { "section": "A", "question_number": "2(vii)", "answer": "17:10", "marks": 2 }, { "section": "A", "question_number": "3(i)(a)", "answer": "In between optical centre and focus", "marks": 1 }, { "section": "A", "question_number": "3(i)(b)", "answer": "Because concave lens produces reduced size image.", "marks": 1 }, { "section": "A", "question_number": "3(ii)", "answer": "No. The geyser draws I = P/V = 1540/220 = 7A. Hence, 5A rated fuse will blow off for the geyser.", "marks": 2 }, { "section": "A", "question_number": "3(iii)", "answer": "1. Increasing the number of turns of the armature\n2. Increasing the applied battery e.m.f.", "marks": 2 }, { "section": "A", "question_number": "3(iv)", "answer": "165,000 J", "marks": 2 }, { "section": "A", "question_number": "3(v)", "answer": "₉₂U²³⁵ + ₀n¹ → ₅₆Ba¹⁴¹ + ₃₆Kr⁹² + 3₀n¹", "marks": 2 }, { "section": "B", "question_number": "4(i)", "answer": "f = 24 cm\nPower = 4.17 D", "marks": 3 }, { "section": "B", "question_number": "4(ii)(a)", "answer": "Microwave", "marks": 1 }, { "section": "B", "question_number": "4(ii)(b)", "answer": "X-rays", "marks": 1 }, { "section": "B", "question_number": "4(ii)(c)", "answer": "Both have same speed in vacuum", "marks": 1 }, { "section": "B", "question_number": "4(iii)(a)", "answer": "Red colour is used as danger signal because it is scattered least due to its longest wavelength in visible range. Hence, it is visible from a very long distance.", "marks": 1 }, { "section": "B", "question_number": "4(iii)(b)1", "answer": "Critical angle is 43°", "marks": 1 }, { "section": "B", "question_number": "4(iii)(b)2", "answer": "Angle of prism = 43°", "marks": 1 }, { "section": "B", "question_number": "4(iii)(b)3", "answer": "If the blue ray is replaced by indigo or violet, there will be total internal reflection.", "marks": 1 }, { "section": "B", "question_number": "5(i)(a)", "answer": "8/9", "marks": 1 }, { "section": "B", "question_number": "5(i)(b)", "answer": "The principle of reversibility", "marks": 1 }, { "section": "B", "question_number": "5(i)(c)", "answer": "No", "marks": 1 }, { "section": "B", "question_number": "5(ii)(a)", "answer": "False", "marks": 1 }, { "section": "B", "question_number": "5(ii)(b)", "answer": "Refractive index = 10t₂/t₁", "marks": 2 }, { "section": "B", "question_number": "5(iii)(a)", "answer": "[Diagram showing completed ray path]", "marks": 2 }, { "section": "B", "question_number": "5(iii)(b)", "answer": "1. Angle of incidence\n2. Refractive index", "marks": 2 }, { "section": "B", "question_number": "6(i)(a)", "answer": "Centre of gravity is the point where the mass of the whole body appears to be concentrated.", "marks": 1 }, { "section": "B", "question_number": "6(i)(b)1", "answer": "2 cm from base (h/3 = 6/3)", "marks": 1 }, { "section": "B", "question_number": "6(i)(b)2", "answer": "Yes", "marks": 1 }, { "section": "B", "question_number": "6(ii)(a)", "answer": "Marble A", "marks": 1 }, { "section": "B", "question_number": "6(ii)(b)", "answer": "Along both the paths", "marks": 1 }, { "section": "B", "question_number": "6(ii)(c)", "answer": "Along both the paths", "marks": 1 }, { "section": "B", "question_number": "6(iii)(a)", "answer": "[Diagram showing tackle system with VR=2]", "marks": 1 }, { "section": "B", "question_number": "6(iii)(b)1", "answer": "M.A. = 1.6", "marks": 1 }, { "section": "B", "question_number": "6(iii)(b)2", "answer": "Effort = 30 kgf", "marks": 2 }, { "section": "B", "question_number": "7(i)(a)", "answer": "Ultrasonic wave", "marks": 1 }, { "section": "B", "question_number": "7(i)(b)", "answer": "1 s", "marks": 2 }, { "section": "B", "question_number": "7(ii)(a)", "answer": "²³⁴₉₀Y → ²³⁴₉₁Z + ⁰₋₁e", "marks": 2 }, { "section": "B", "question_number": "7(ii)(b)", "answer": "U-235", "marks": 1 }, { "section": "B", "question_number": "7(iii)(a)", "answer": "Resonance", "marks": 1 }, { "section": "B", "question_number": "7(iii)(b)", "answer": "Natural frequency of the air column matched with the frequency of the tuning fork.", "marks": 1 }, { "section": "B", "question_number": "7(iii)(c)", "answer": "Length of air column should be decrease. Since frequency is inversely proportional to the air column.", "marks": 2 }, { "section": "B", "question_number": "8(i)(a)", "answer": "Non-ohmic", "marks": 1 }, { "section": "B", "question_number": "8(i)(b)", "answer": "The resistance is not constant. It increases as voltage and current increases.", "marks": 1 }, { "section": "B", "question_number": "8(i)(c)", "answer": "The flow of current through the conductor is directly proportional to the potential difference established across the conductor provide its physical conditions are constant.", "marks": 2 }, { "section": "B", "question_number": "8(ii)(a)", "answer": "Step down transformer", "marks": 1 }, { "section": "B", "question_number": "8(ii)(b)", "answer": "Wire of secondary coil is thicker because secondary current is higher than primary current.", "marks": 1 }, { "section": "B", "question_number": "8(iii)(a)", "answer": "8Ω", "marks": 1 }, { "section": "B", "question_number": "8(iii)(b)", "answer": "0.5A", "marks": 1 }, { "section": "B", "question_number": "8(iii)(c)", "answer": "Current in both the resistors are equal because both the arms have same resistance value.", "marks": 2 }, { "section": "B", "question_number": "9(i)", "answer": "25g", "marks": 3 }, { "section": "B", "question_number": "9(ii)(a)", "answer": "When lake freezes, it released latent heat to the atmosphere which warms the atmosphere.", "marks": 1 }, { "section": "B", "question_number": "9(ii)(b)", "answer": "Since there is no change of temperature there is no change in kinetic energy.", "marks": 1 }, { "section": "B", "question_number": "9(ii)(c)", "answer": "1 g of ice at 0°C has more heat energy than 1 g water at 0°C.", "marks": 1 }, { "section": "B", "question_number": "9(iii)(a)", "answer": "Number of turns in armature may be increased.", "marks": 1 }, { "section": "B", "question_number": "9(iii)(b)1", "answer": "Maxwell right hand thumb rule.", "marks": 1 }, { "section": "B", "question_number": "9(iii)(b)2", "answer": "Direction of current is from X to Y.", "marks": 1 }, { "section": "B", "question_number": "9(iii)(b)3", "answer": "As R increases, current decreases. So, strength of magnetic field decreases.", "marks": 1 } ]