GRADE 9 NATURAL SCIENCE MODEL ANSWER FOR JUNE

GRADE 9 NATURAL SCIENCE – MODEL ANSWER FOR JUNE 2011 EXAM SECTION A Question 1 1. 1 Diffuse/ irregular /scattered 1. 6 Refractive Index 1. 2 Dispersion 1. 7 Kilowatt hour 1. 3 Transparent 1. 8 Inertia 1. 4 Power/ Watt 1. 9 Red 1. 5 Force 1. 10 105 N Question 2 2. 1 C 2. 6 A 2. 2 C 2. 7 B 2. 3 A 2. 8 B 2. 4 C 2. 9 A 2. 5 D 2. 10 B

Question 3 3. 1. 1 Plane / Regular 3. 1. 2 BC = Incident Ray EC = Normal C = Point of incidence CD = Reflected Ray 3. 1. 3 Equal or lie in the same plane 3. 1. 4 Regular 3. 1. 5 Real, can be cast on a screen, inverted (upside down) Question 4 4. 1 Red 4. 4. 2. 1 Black 4. 2 Violet 4. 4. 2. 2 Black 4. 3 Red 4. 4. 2. 3 Blue 4. 4. 2. 4 Black 4. 4. 1 All Colours 4. 4. 2. 5 Red

4. 5 Labels : Air/water Virtual Image Rays in water Rays deviated away from normal in air Normals Construction lines broken Question 5 5. 1. 1 15 k. Wh 5. 2 Coal non-renewable energy 5. 1. 2 R 11. 85 Source. Pollution in Air 5. 1. 3 60 k. Wh SO 2 => Acid Rain; 5. 1. 4 R 25. 65 CO 2 => Global warming

5. 3 2800 x 30/60 = 1400 Wh 1500 x 10/60 = 250 Wh 3500 x 30/60 = 1750 Wh 3400 Wh / 1000 Therefore cost = 3. 4 x 0. 79 = R 2. 69 Question 6 6. 1. 1. 30 x 1. 5 =45 kg Therefore Fg = 45 x 10 = 450 N 6. 1. 3. 2750 J 6. 1. 5 P= 6. 1. 2. W = F x Change in X = (450+100) x 5 = 2750 J 6. 1. 4 Gravitational Potential W/t 2750/120 Therefore Power = 22. 92 W