Raffles Institution 2020 Y4 FE Sections A and B

1 Section A [35 marks] Four possible answers A, B, C and D are given for each question. Choose the most appropriate answer and shade your answers in pencil on the OMR answer sheet provided. 1 Which row contains only base quantities? A time, temperature, weight B potential difference, length, mass C charge, temperature, length D amount of substance, current, mass 2 Four students each make a series of measurements of the acceleration due to gravity g. The table shows the results. Which student obtains a set of results that can be described as accurate but not precise? student results, g / m s−2 A 9.81 9.82 9.83 B 8.57 9.79 11.05 C 7.90 8.12 9.25 D 8.47 8.49 8.49 3 A hot air balloon ascends from rest with an acceleration of 2.50 m s −2, in the absence of air resistance. When it reaches a height of 48.0 m above the initial ground level, an object of mass 5.00 kg is released from the balloon. What is the speed of the object just before it impacts the ground? A 28.3 m s−1 B 31.1 m s−1 C 34.4 m s−1 D 35.8 m s−1

2 4 A tennis ball is thrown vertically up, hitting the ceiling before it falls down. Which graph best represents the variation with time t of the velocity v of the ball before and after hitting the ceiling? Assume that the effect of air resistance is negligible. A B C D 5 Which is a scalar quantity? A air resistance B mass C displacement D velocity 6 Three forces, 3.0 N, 4.0 N and 5.0 N are added to obtain a resultant force R. What is the minimum value of R? A 0 N B 2.0 N C 4.0 N D 6.0 N 7 Which situation will friction be classified as a nuisance? A car braking B heat generated when a box is pushed across a rough surface C person holding an object D student walking t t t v v v v 0 0 0 0 t

3 8 A machine is able to lift a solid object with maximum mass of 600 kg on the surface of the earth. The same machine is able to lift another solid object with maximum mass of 3600 kg on the surface of the moon. Why is this so? A The mass of the machine is lesser on the surface of the moon than on the surface of the earth. B The weight of the machine is lesser on the surface of the moon than on the surface of the earth. C The mass of the 3600 kg object is lesser on the surface of the moon than on the surface of the earth. D The weight of the 3600 kg object is lesser on the surface of the moon than on the surface of the earth. 9 A thin square plate has the triangular region A removed. Which region of the plate does the centre of gravity now lie? A B C D

4 0.80 m m / s 10 An uniform thin rod of mass 20.0 g is balanced when a pivot is placed at point X. The pivot is now shifted l cm to the left of its current position to a point Y, and an object of 40.0 g is placed on the rod to balance this new arrangement. Where should the object be placed? A 0.5l cm to the left of X B 0.5l cm to the left of Y C l cm to the left of Y D 2l cm to the left of Y 11 The diagram shows a 0.50 kg toy car moving up a rough slope with an initial speed of 2.5 m / s. It is only able to move a distance of 0.80 m up the slope to its highest point 0.28 m above the ground. What is the average resistive force acting on the toy car as it moves up the slope? A 0.236 N B 1.72 N C 1.95 N D 3.67 N l rod X Y highest position of the toy car initial position of the toy car with speed of 2.5 m / s 0.80 m 0.28 m ground

5 12 The diagram below shows the displacement-distance graph of a longitudinal wave in air. 0 What is the region at point X and point Y? X Y A rarefaction rarefaction B crest trough C compression compression D compression rarefaction 13 The diagram shows circular wavefronts travelling from region P into Q and then into R in a ripple tank. Which are the shallowest and deepest regions? shallowest region deepest region A R P B Q P C Q R D P R displacement X Y distance P Q R direction of wave travel

6 14 The table shows the boiling point of three different substances. substance alcohol ether hexane boiling point / °C 79 35 68 How many of the above three substances will be in liquid state at a temperature of 77 °C? A none B one C two D three 15 The figure shows a saucepan used for cooking. Which combination best describes the thermal properties of the insulating handle? specific heat capacity melting point A low low B low high C high low D high high handle

7 16 The diagram shows a puddle of water on a pavement. Which factor does not affect the rate of evaporation of the water? A depth of water B humidity of surrounding air C surface area of water D temperature of water 17 Three electrical conductors mounted on insulating stands , are placed close to one another without touching. Conductor X is positively charged. Both conductors Y and Z are neutral. After conductor Z is earthed momentarily, what is the charge on conductor Z? A neutral B positive C negative D the charge cannot be determined X Y Z insulating stands

8 α β 18 Two charged conducting spheres P and Q are suspended near each other using insulated strings as shown. Sphere P has a smaller net charge than sphere Q, and angle α is greater than angle β. Which statement is correct? A Sphere P has a greater mass than sphere Q. B Sphere P experiences a greater electric force of repulsion than sphere Q. C Sphere Q experiences a greater electric force of attraction than sphere P. D Sphere Q experiences a greater tension than sphere P. 19 Which situation does not describe a possible solution to prevent electrostatic charging from becoming a potential hazard? A Wearing a conducting wrist strap that is connected to the ground when handling electronic components B Connecting a copper strip from the top of a building into the ground C Hanging a metal chain from a moving lorry to the ground D Replacing the tyres of airplanes with insulating rubber P Q

9 20 A wire carries a current of 10 A. The charge of a single electron is 1.60 x 10–19 C. How many electrons pass through a given cross section of the wire in one minute? A 1.0 x 1016 B 1.0 x 1018 C 3.8 x 1019 D 3.8 x 1021 21 The diagram shows a circuit with a battery of e.m.f. 4.0 V, connected to two resistors of resistance 2.0 Ω, an ammeter and a voltmeter. What are the readings on the ammeter and the voltmeter when the switch is closed? ammeter reading / A voltmeter reading / V A 1.0 0.0 B 2.0 0.0 C 1.0 2.0 D 2.0 2.0 2.0 Ω 4.0 V 2.0 Ω

10 22 6.0 J of energy is supplied by a battery when 3.0 C of electrons passes through it. What is the electromotive force (e.m.f.) of the battery? A 0.50 V B 2.0 V C 3.0 V D 18 V 23 Three identical resistors are connected across PQ. Which combination has the lowest effective resistance across PQ? A B C D P Q P Q P Q P Q