Length of Simple Pendulum - Physics - Exam Paper, Exams of Physics

Download Length of Simple Pendulum - Physics - Exam Paper and more Exams Physics in PDF only on Docsity! LEAVING CERTIFICATE EXAMINATION 2006: PHYSICS – HIGHER LEVEL 2006 Question 1 In investigating the relationship between the period and the length of a simple pendulum, a pendulum was set up so that it could swing freely about a fixed point. The length l of the pendulum and the time t taken for 25 oscillations were recorded. This procedure was repeated for different values of the length. The table shows the recorded data. l/cm 40.0 50.0 60.0 70.0 80.0 90.0 100.0 t/s 31.3 35.4 39.1 43.0 45.5 48.2 50.1 The pendulum used consisted of a small heavy bob attached to a length of inextensible string. (i) Explain why a small heavy bob was used. (ii) Explain why the string was inextensible. (iii) Describe how the pendulum was set up so that it swung freely about a fixed point. (iv) Give one other precaution taken when allowing the pendulum to swing. (v) Draw a suitable graph to investigate the relationship between the period of the simple pendulum and its length. (vi) What is this relationship? Justify your answer. 2006 Question 2 In an experiment to measure the wavelength of monochromatic light, a narrow beam of the light fell normally on a diffraction grating. The grating had 300 lines per millimetre. A diffraction pattern was produced. The angle between the second order image to the left and the second order image to the right of the central bright image in the pattern was measured. The angle measured was 40.60. (i) Describe, with the aid of a labelled diagram, how the data was obtained. (ii) How was a narrow beam of light produced? (iii) Use the data to calculate the wavelength of the monochromatic light. (iv) Explain how using a diffraction grating of 500 lines per mm leads to a more accurate result. (v) Give another way of improving the accuracy of this experiment. 2006 Question 3 A cylindrical column of air closed at one end and three different tuning forks were used in an experiment to measure the speed of sound in air. A tuning fork of frequency f was set vibrating and held over the column of air. The length of the column of air was adjusted until it was vibrating at its first harmonic and its length l was then measured. This procedure was repeated for each tuning fork. Finally, the diameter of the column of air was measured. The following data was recorded. f/Hz 512 480 426 l/cm 16.0 17.2 19.4 Diameter of column of air = 2.05 cm (i) Describe how the length of the column of air was adjusted. (ii) Describe how the frequency of the column of air was measured. (iii) Describe how the diameter of the column of air was measured. (iv) How was it known that the air column was vibrating at its first harmonic? (v) Using all of the data, calculate the speed of sound in air. 2006 Question 4 In an experiment to verify Joule’s law a student passed a current through a heating coil in a calorimeter containing a fixed mass of water and measured the rise in temperature Δθ for a series of different values of the current I. The student allowed the current to flow for three minutes in each case. (i) Describe, with the aid of a labelled diagram, how the student arranged the apparatus. (ii) Why was a fixed mass of water used throughout the experiment? (iii) The student drew a graph, as shown. Explain how this graph verifies Joule’s law. (iv) Given that the mass of water in the calorimeter was 90 g in each case, and assuming that all of the electrical energy supplied was absorbed by the water, use the graph to determine the resistance of the heating coil. The specific heat capacity of water is 4200 J kg–1 K–1. 2006 Question 5 (a) State Newton’s third law of motion. (b) Why is it easier to turn a nut using a longer spanner than a shorter one? (c) The average value for the solar constant in Ireland is 1.2 × 102 W m–2. What is the average energy falling normally on an area of 5 m2 of ground in Ireland in 1 minute? (d) A sound wave is diffracted as it passes through a doorway but a light wave is not. Explain why. (e) What is the Doppler effect? (f) An RCD is rated 30 mA. Explain the significance of this current. (g) Why is Coulomb’s law an example of the inverse square law? (h) Sketch a graph to show the variation of current with potential difference for a semiconductor diode in forward bias. (i) Describe the Bohr model of the atom. (j) Name the three negatively charged leptons. or How can a galvanometer be converted into a voltmeter? 2006 Question 6 (i) Define velocity. (ii) Define angular velocity. (iii) Derive the relationship between the velocity of a particle travelling in uniform circular motion and its angular velocity. (iv) A student swings a ball in a circle of radius 70 cm in the vertical plane as shown. The angular velocity of the ball is 10 rad s–1. What is the velocity of the ball? (v) How long does the ball take to complete one revolution? (vi) Draw a diagram to show the forces acting on the ball when it is at position A. (vii) The student releases the ball when is it at A, which is 130 cm above the ground, and the ball travels vertically upwards. Calculate the maximum height, above the ground, the ball will reach. (viii) Calculate the time taken for the ball to hit the ground after its release from A. (acceleration due to gravity = 9.8 m s–2) 2006 Question 7 (i) What is meant by the refraction of light? (ii) A converging lens is used as a magnifying glass. Draw a ray diagram to show how an erect image is formed by a magnifying glass. (iii) A diverging lens cannot be used as a magnifying glass. Explain why. (iv) The converging lens has a focal length of 8 cm. Determine the two positions that an object can be placed to produce an image that is four times the size of the object? (v) The power of an eye when looking at a distant object should be 60 m–1. A person with defective vision has a minimum power of 64 m–1. Calculate the focal length of the lens required to correct this defect. (vi) What type of lens is used? (vii) Name the defect.