SET C PAPER 2 QUESTION

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1 Sec 4 Physics Exam papers with worked solutions SET C PAPER 2 QUESTION Compiled by THE PHYSICS CAFE 1

2 READ THESE INSTRUCTIONS FIRST Write your name, class and index number on the cover page of this Question Paper and all the work you hand in. Write in dark blue or black pen on both sides of the paper. You may use a soft pencil for any diagrams or graphs. Do not use staples, paper clips, highlighters, glue or correction fluid. Section A Answer all questions. Section B Answer all questions. Question 11 has a choice of parts to answer. Candidates are reminded that all quantitative answers should include appropriate units. Candidates are advised to show all their working in a clear and orderly manner, as more marks are awarded for sound use of Physics than for correct answers. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. Unless otherwise stated, take the acceleration of free fall, g, to be 10 m/s 2. ThePhysicsCafe 2

3 Section A (50 marks) Answer all questions from this section. 1 A gun is loaded with a bullet of mass 30 g. The gun is then fired. (a) What is the kinetic energy of the bullet if its speed is 500 m/s? kinetic energy =... [2] (b) After 1.0 ms, the bullet hits a solid concrete wall, creates a 5.0 cm deep hole and is embedded in the hole. What is the retarding force of the concrete? [Assume that there is no energy loss to the surroundings during the flight of the bullet.] force =... [2] (c) How long does it take the bullet to decelerate to a stop? 3

4 (d) time =... [2] On Fig. 1.1, sketch the speed-time graph of the bullet after it is fired to the time it comes to a stop embedded in the wall. v / ms -1 Fig A 1.5 kg bottle weighing 15 N was attached to a string and hung from the ceiling. A strong wind blew horizontally on the bottle, moving it to one side. The bottle made a 45 o angle with the vertical as shown in Fig Fig. 2.1 (a) On Fig. 2.1, draw all the forces acting on the bottle. [2] 45 o t / ms ThePhysicsCafe [2] 4

5 (b) By scale drawing, using 1.0 cm to represent 2.0 N, determine the tension in the string. tension =... [3] (c) If the string were to break, what would be the acceleration of the bottle? 5

6 acceleration = [2] 3 Fig. 3.1 shows a nut between the jaws of a nutcracker. Forces F are applied to the handles, at points 14.0 cm from the hinge H. The contact between the nutcracker and nut is effectively 3.0 cm from H. (a) F 3.0 cm Fig. 3.1 Explain the advantage of applying the force near the ends of the handle [1] (b) Take into consideration the forces acting on the right handle only in Fig cm H H Fig cm F 14.0 cm ThePhysicsCafe F 6

7 (i) Determine the force acting on the nut when F = 4.0 N. (The nutcracker is not moving) force =... [2] (ii) What is the ratio of any applied force at the handles to the corresponding force acting on the nut? ratio =... [1] (c) Why are the forces on the left handle not considered for the calculation in part (b)(i)? [1] 7

8 4 (a) Consider a rectangular tank of dimensions 70 cm by 48 cm by 90 cm which is filled to the brim with glycerine of density 1.26 g/cm 3 as shown in Fig (i) (ii) 70cm Define pressure. 90cm glycerin Fig cm... [1] Calculate the pressure exerted by the glycerine on the bottom of the rectangular tank. pressure =... [2] ThePhysicsCafe 8

9 (b) A copper rod is heated at one end X by a Bunsen flame as shown in Fig An iron nail initially stuck on the other end Y of the rod falls off after t minutes. Fig. 4.2 (i) Describe, in terms of the motion of particles, how the temperature of end Y rises.... [2] (ii) If the copper rod is replaced by a metal rod whose heat capacity is larger, describe and explain any change in the value of t.... [2] 9

5 Fig. 5.1 shows a radiation fan heater used in homes during winter to keep the room warm. (a) (b) Fig. 5.1 State the main processes of heat transfer by the heater to warm up the whole room.

At room temperature, the density of air is 1.25 kg/m 3.

10 5 Fig. 5.1 shows a radiation fan heater used in homes during winter to keep the room warm. (a) (b) Fig. 5.1 State the main processes of heat transfer by the heater to warm up the whole room [1] The heater is switched on in a bedroom. The bedroom has dimensions 5 m by 4 m by 3 m. At room temperature, the density of air is 1.25 kg/m 3. (i) If the heater operates at 500 W, calculate the energy produced by the fan in one hour. ThePhysicsCafe energy produced =... [2] 10

11 (ii) Calculate the mass of air in the bedroom. mass =... [1] (iii) Hence, calculate the increase in the temperature in the bedroom after the heater has operated for an hour. Specific heat capacity of air, cair = 1000 J/(kg K) increase in temperature =... [2] (c) Should the fan heater be placed at the top or at the bottom of the bedroom? Explain your answer in terms of density changes [2] 11

12 6 A converging lens can be used to perform many optical roles, and they depend on the position of the object with respect to the lens. (a) (b) (c) Suggest a possible use of the lens if (i) (ii) the rays do not converge at a point after passing through the lens.... [1] the image formed is real and enlarged.... [1] On Fig. 6.1, sketch a ray diagram to show where an object is positioned with respect to the converging lens to form a diminished image. Mark clearly the principal focus of the lens (F) and the object (O). Fig. 6.1 image ThePhysicsCafe Both mirrors and lenses can be used for imaging in many optical instruments. Suggest one advantage of using mirrors compared to lens [1] [3] 12

13 7 Fig. 7.1 shows a positively charged light metal sphere hung on an insulating thread P Fig. 7.1 Fig. 7.2 A metal plate P mounted on an insulating stand and connected to earth is brought near to the sphere, which moves into the deflected position shown in Fig (a) On Fig. 7.2, mark the charges on the sphere and metal plate P. Explain why the charges on plate P are positioned this way [2] (b) Explain why the sphere is deflected as shown [1] 13

14 8 Fig. 8.1 shows part of the mains electrical circuit in a house. Two lamps A and B, each rated at 60 W 240 V, are connected to the live wire through fuse X. An electric kettle, rated at 840 W 240 V, is connected to the live wire though fuse Y. Fuse Z protects the whole circuit. The electric kettle has a metal case which is connected to Earth. The mains supply voltage is 240 V. (a) (b) Fig. 8.1 Calculate the current in fuse Z when the electric kettle and both the lamps are switched on. current =... [3] A fault develops in the electric kettle, causing a current of 10 A in fuse Y. The lamps A and B remain switched on. The maximum current ratings of the fuses are shown in Fig ThePhysicsCafe Fuse X Fuse Y Fuse Z Current rating / A Fig. 8.2 Describe and explain what happens to each of the fuses X, Y and Z at the instant when the fault develops

15 ... Section B (30 marks) [3] Answer all questions from this section. Answer only one of the two alternative questions in Question Fig. 9.1 below shows the graph of the variation of resistance with the temperature of a thermistor Resistance / k Temperature / C Fig. 9.1 (a) Calculate the current flowing through the thermistor at 30 C when it is connected to a 12 V supply. 15

16 current =... [2] (b) (c) Plot a current-temperature graph for this thermistor in Fig Assume that the thermistor is still connected to the 12 V supply. Fig. 9.2 The thermistor is used in a 12 V potential divider circuit of an air-conditioning unit to regulate the temperature of a room. The air-conditioning unit is automatically switched on when the temperature is high and the output voltage Vout of the potential divider circuit is 8.0 V. ThePhysicsCafe (i) Draw a circuit diagram of this potential divider circuit. Label the output voltage Vout accordingly. [3] 16

17 [2] (ii) If the air-conditioning unit is automatically switched on when the temperature of the room is 30 C, calculate the resistance of the other resistor in the potential divider circuit. resistance =... [2] (d) Suggest one other appliance or application that uses a thermistor.... [1] 17

10 In the early 1970 s, batteries were expensive and many cyclists usually used a dynamo (Fig. 10.1) to power up their torchlight, which they used as a headlamp on their bicycles.

18 10 In the early 1970 s, batteries were expensive and many cyclists usually used a dynamo (Fig. 10.1) to power up their torchlight, which they used as a headlamp on their bicycles. The dynamo was placed near the tyres of the bicycle such that if they needed the torchlight to turn on, the rotating wheel was put in contact with the tyres of the bicycle. When the tyres rotated, the wheel would rotate, causing the magnet to rotate and current will then flow in the torchlight as shown in Fig (a) (i) State the poles induced at the points labelled A and B in Fig when the magnet is at the position shown. (ii) Fig dynamo A: B: [1] Explain why there is a current produced when the magnet is rotated. B A Fig ThePhysicsCafe 18

19 ... [2] (iii) Explain why the current produced is an alternating one.... [2] (iv) State one advantage of using a rotating magnet rather than a rotating coil to produce electricity.... [1] 19

20 (b) A CRO is attached to the output of the dynamo and the following trace is obtained in Fig (i) Fig State the peak voltage, period and frequency of rotation. ThePhysicsCafe (ii) Peak Voltage:... Period:... Frequency:... [2] Draw, on the CRO in Fig. 10.3, the new trace if the cyclist is pedalling twice as fast. [2] 20

21 11 EITHER Fig shows a simple experimental set-up to study the motion of a motor. AB and CD are solenoids connected to a battery. F and G are connected to an external voltage supply. The graph of the external voltage supplied is as shown in Fig (Positive voltage indicates that the potential of F is higher than of G). It is observed that the coil makes 5 rotations in one minute. Fig Fig (a) (i) Identify the magnetic poles at B and C. B:. C:. [1] (ii) How would the coil turn (clockwise or anticlockwise direction) during the first minute?... [1] (iii) Explain how you arrived to the answer in (ii). 21

22 [2] (iv) Explain, in terms of magnetic fields, why the coil would turn when a current flows in the direction PQRS during the first minute. You may want to include diagrams to make your explanation clearer. ThePhysicsCafe... [2] (v) State what would happen to the coil during the 1-2 minute interval. 22

23 Sec 4 Physics Set C Paper 2... [1] (b) Describe an experiment to determine the motor starting current (minimum current that would make the motor start to rotate) In your account, draw a labelled diagram of the apparatus, describe the procedure you use to obtain the readings. You may include other apparatus in the set up that would allow you to determine the current

11 OR Sec 4 Physics Set C Paper 2............ [3] The Hubble Space Telescope (HST) in Fig. 11.

24 11 OR Sec 4 Physics Set C Paper [3] The Hubble Space Telescope (HST) in Fig is a space telescope sent into orbit outside Earth s atmosphere to capture detailed images from space since The telescope instruments capture images in ultraviolet, infrared and visible radiation. These images are processed before they are transmitted back to Earth twice daily in microwave. (a) (b) Fig Four different types of radiation are shown in bold. List them in the order of increasing frequency. ThePhysicsCafe... [1] The various types of radiation are components of the electromagnetic spectrum and are considered transverse waves. Explain what is meant by a transverse wave [1] (c) Suggest and explain why ultrasound wave is not used for transmission of signals from the space telescope. 24

25 Sec 4 Physics Set C Paper [2] (d) One main reason for sending the HST out of the Earth s atmosphere is that our atmosphere blocks out most of the ultraviolet radiation. Less comprehensive images will be revealed without the use of UV rays. (i) State two other uses of ultraviolet radiation.... [2] (ii) HST captures the outer space images using near-ultraviolet which carries a typical wavelength about 350 nm. Determine the corresponding frequency. frequency =..[2] (iii) Other regions of the electromagnetic spectrum which have shorter wavelength than UV rays can cause ionisation. Astronauts sent into outer space must put on proper space suits to minimise direct exposure to the ionising radiation. Explain what is meant by ionisation and describe one harmful effect it has on astronauts. 25

26 ... [2] End of Paper ThePhysicsCafe 26

Cambridge International Examinations Cambridge Ordinary Level

Cambridge International Examinations Cambridge Ordinary Level *6032081406* PHYSICS 5054/22 Paper 2 Theory May/June 2018 1 hour 45 minutes Candidates answer on the Question Paper. No Additional Materials