Acceleration Due to Gravity - Physics - Exam Paper, Exams of Physics

Download Acceleration Due to Gravity - Physics - Exam Paper and more Exams Physics in PDF only on Docsity! LEAVING CERTIFICATE EXAMINATION 2008: PHYSICS – HIGHER LEVEL 2008 Question 1 A student investigated the relationship between the period and the length of a simple pendulum. The student measured the length l of the pendulum. The pendulum was then allowed to swing through a small angle and the time t for 30 oscillations was measured. This procedure was repeated for different values of the length of the pendulum. The student recorded the following data: l /cm 40.0 50.0 60.0 70.0 80.0 90.0 100.0 t /s 38.4 42.6 47.4 51.6 54.6 57.9 60.0 (i) Why did the student measure the time for 30 oscillations instead of measuring the time for one? (ii) How did the student ensure that the length of the pendulum remained constant when the pendulum was swinging? (iii) Using the recorded data draw a suitable graph to show the relationship between the period and the length of a simple pendulum. (iv) What is this relationship? (v) Use your graph to calculate the acceleration due to gravity. 2008 Question 2 In an experiment to measure the specific latent heat of fusion of ice, warm water was placed in a copper calorimeter. Dried, melting ice was added to the warm water and the following data was recorded. Mass of calorimeter 60.5 g Mass of calorimeter + water 118.8 g Temperature of warm water 30.5 oC Mass of ice 15.1 g Temperature of water after adding ice 10.2 oC (i) Explain why warm water was used. (ii) Why was dried ice used? (iii) Why was melting ice used? (iv) Describe how the mass of the ice was found (v) What should be the approximate room temperature to minimise experimental error? (vi) Calculate the energy lost by the calorimeter and the warm water; (vii) Calculate the specific latent heat of fusion of ice. (specific heat capacity of copper = 390 J kg–1 K–1; specific heat capacity of water = 4200 J kg–1 K–1) 2008 Question 3 In an experiment to measure the wavelength of monochromatic light, a diffraction pattern was produced using a diffraction grating with 500 lines per mm. The angle between the first order images was measured. This was repeated for the second and the third order images. The table shows the recorded data: Angle between first order images Angle between second order images Angle between third order images 34.20 71.60 121.60 (i) Draw a labelled diagram of the apparatus used in the experiment. (ii) Explain how the first order images were identified. (iii) Describe how the angle between the first order images was measured. (iv) Use the data to calculate the wavelength of the monochromatic light. 2008 Question 4 A student investigated the variation of the resistance R of a metallic conductor with its temperature θ. The student recorded the following data. θ/oC 20 30 40 50 60 70 80 R/Ω 4.6 4.9 5.1 5.4 5.6 5.9 6.1 (i) Describe, with the aid of a labelled diagram, how the data was obtained. (ii) Draw a suitable graph to show the relationship between the resistance of the metal conductor and its temperature. (iii) Use your graph to estimate the resistance of the metal conductor at a temperature of –20 oC; (iv) Use your graph to estimate the change in resistance for a temperature increase of 80 oC; (v) Use your graph to explain why the relationship between the resistance of a metallic conductor and its temperature is linear. (This was mistakenly termed ‘non-linear’ in the original exam paper). 2008 Question 5 a) State the law of flotation. b) The head of a thumbtack has an area of 500 mm2. Its point has an area of 0.3 mm2. The pressure exerted at the head of the thumbtack is 12 Pa. What is the pressure exerted at the point of the thumbtack? c) What is the relationship between the frequency of a vibrating stretched string and its length? d) Why does diffraction not occur when light passes through a window? e) Why is a fluorescent tube an efficient source of light? f) What is the force exerted on an electron when it is in an electric field of strength 5 N C–1? g) What are the charge carriers when an electric current (i) passes through a semiconductor; (ii) passes through an electrolyte? h) Give two ways of deflecting a beam of electrons. i) Name an instrument used to detect radioactivity. What is the principle of operation of this instrument? j) The existence of the neutrino was proposed in 1930 but it was not detected until 1956. Give two reasons why it is difficult to detect a neutrino. 2008 Question 6 (i) State Newton’s law of universal gravitation. (ii) The international space station (ISS) moves in a circular orbit around the equator at a height of 400 km. What type of force is required to keep the ISS in orbit? (iii) What is the direction of this force? (iv) Calculate the acceleration due to gravity at a point 400 km above the surface of the earth. (v) An astronaut in the ISS appears weightless. Explain why. (vi) Derive the relationship between the period of the ISS, the radius of its orbit and the mass of the earth. (vii) Calculate the period of an orbit of the ISS. (viii) After an orbit, the ISS will be above a different point on the earth’s surface. Explain why. (ix) How many times does an astronaut on the ISS see the sun rise in a 24 hour period? (gravitational constant = 6.6 × 10–11 N m2 kg–2; mass of the earth = 6.0 × 1024 kg; radius of the earth = 6.4 × 106 m) 2008 Question 7 (i) Define resistivity and give its unit of measurement. (ii) An electric toaster heats bread by convection and radiation. What is the difference between convection and radiation as a means of heat transfer? (iii) A toaster has a power rating of 1050 W when it is connected to the mains supply. Its heating coil is made of nichrome and it has a resistance of 12 Ω. The coil is 40 m long and it has a circular cross-section of diameter 2.2 mm. Calculate the resistivity of nichrome. (iv) Calculate the heat generated by the toaster in 2 minutes if it has an efficiency of 96%. (v) The toaster has exposed metal parts. How is the risk of electrocution minimised? (vi) When the toaster is on, the coil emits red light. Explain, in terms of movement of electrons, why light is emitted when a metal is heated. 2008 Question 8 (i) What is electromagnetic induction? (ii) State the laws of electromagnetic induction. (iii) A bar magnet is attached to a string and allowed to swing as shown in the diagram. A copper sheet is then placed underneath the magnet. Explain why the amplitude of the swings decreases rapidly. (iv) What is the main energy conversion that takes place as the magnet slows down? (v) A metal loop of wire in the shape of a square of side 5 cm enters a magnetic field of flux density 8 T. The loop is perpendicular to the field and is travelling at a speed of 5 m s–1. How long does it take the loop to completely enter the field? (vi) What is the magnetic flux cutting the loop when it is completely in the magnetic field?