Physics Exam Paper: Waves, Optics, and Electromagnetism, Exams of Biomechanics

Download Physics Exam Paper: Waves, Optics, and Electromagnetism and more Exams Biomechanics in PDF only on Docsity! *JUN217407201* IB/M/Jun21/E7 7407/2 For Examiner’s Use Question Mark 1 2 3 4 5 6–35 TOTAL Materials For this paper you must have: • a pencil and a ruler • a scientific calculator • a Data and Formulae Booklet • a protractor. Instructions • Use black ink or black ball-point pen. • Fill in the boxes at the top of this page. • Answer all questions. • You must answer the questions in the spaces provided. Do not write outside the box around each page or on blank pages. • If you need extra space for your answer(s), use the lined pages at the end of this book. Write the question number against your answer(s). • Do all rough work in this book. Cross through any work you do not want to be marked. • Show all your working. Information • The marks for questions are shown in brackets. • The maximum mark for this paper is 70. • You are expected to use a scientific calculator where appropriate. • A Data and Formulae Booklet is provided as a loose insert. Please write clearly in block capitals. Centre number Candidate number Surname Forename(s) Candidate signature I declare this is my own work. AS PHYSICS Paper 2 Time allowed: 1 hour 30 minutes You are advised to spend about 35 minutes on Section C 2 *02* IB/M/Jun21/7407/2 Do not write outside the box Section A Answer all questions in this section. 0 1 A student investigates stationary waves using microwaves. Figure 1 shows a metre ruler fixed to a bench. The student places a microwave transmitter T at one end of the ruler and a vertical metal reflector R at the other end. R is at a right angle to the ruler. Figure 1 The student places a microwave detector D approximately one-third of the distance from T to R. When T is switched off, the microammeter connected to D reads zero. When T is switched on, stationary waves are produced between T and R, and the microammeter registers a current. When the student moves D along the ruler, the size of the current changes between maximum and minimum values. 5 *05* Turn over ► IB/M/Jun21/7407/2 Do not write outside the box 0 1 . 5 Figure 4 shows D placed at a position where the current is a maximum. Figure 4 The student rotates D by 90°, without changing its distance from T, to the position shown in Figure 5. The current is now zero. Figure 5 State the property of microwaves that is shown by this change in current. [1 mark] 9 6 *06* IB/M/Jun21/7407/2 Do not write outside the box 0 2 A student does an experiment to determine the Young modulus of a metal. Figure 6 shows a wire made from the metal clamped at points A and B so that the wire is horizontal. The horizontal distance between A and B = 3.00 m. C is the mid-point on the wire between A and B. Figure 6 A mass of weight W is suspended at C to extend the wire. Figure 7 shows that C moves vertically downwards by a distance y. Figure 7 7 *07* Turn over ► IB/M/Jun21/7407/2 Do not write outside the box 0 2 . 1 When W is 1.0 N, y is 6.34 cm. Show that the wire extends by approximately 3 mm. [1 mark] 0 2 . 2 Calculate the tension in the wire when W is 1.0 N. [2 marks] tension = N Question 2 continues on the next page 10 *10* IB/M/Jun21/7407/2 Do not write outside the box 0 3 Figure 9 shows a micrometer screw gauge used to measure the diameter of a pencil. Figure 9 11 *11* Turn over ► IB/M/Jun21/7407/2 Do not write outside the box 0 3 . 1 State the reading on the micrometer. [1 mark] reading = unit = 0 3 . 2 The micrometer has a zero error. Describe how to determine an accurate measurement for the diameter of the pencil using this micrometer. [2 marks] END OF SECTION A 3 12 *12* IB/M/Jun21/7407/2 Do not write outside the box Section B Answer all questions in this section. 0 4 Figure 10 shows a conveyor used to raise concrete blocks on a building site. The blocks do not slip on the belt at any time. Figure 10 Figure 11 shows an enlarged view of one block on the belt. The belt is inclined at 23° to the horizontal. The mass of the block is 19 kg. Figure 11 The belt exerts a frictional force F on the block when the block is at rest. 0 4 . 1 Draw an arrow on Figure 11 to show the line of action of F. [1 mark] 15 *15* Turn over ► IB/M/Jun21/7407/2 Do not write outside the box 0 5 . 1 A light emitting diode (LED) emits blue light with a wavelength of 440 nm. The rate of photon emission is 3.0 × 1016 s−1. Show that the power output of the LED is approximately 0.014 W. [2 marks] Question 5 continues on the next page 16 *16* IB/M/Jun21/7407/2 Do not write outside the box 0 5 . 2 A different LED emits red light with a wavelength of 660 nm. Figure 12 shows how the rate of photon emission varies with current up to the maximum operating current of this LED. Figure 12 A student claims that the red LED can have twice the power output of the blue LED. Deduce whether the student’s claim is correct. [3 marks] 17 *17* Turn over ► IB/M/Jun21/7407/2 Do not write outside the box 0 5 . 3 The student has paint that fluoresces when light of any wavelength is incident on it. She coats the blue LED and the red LED with the paint. Compare the wavelengths of light emitted by the paint on each LED. In your answer you should also explain the processes that cause the paint to fluoresce. [6 marks] END OF SECTION B 11 20 *20* IB/M/Jun21/7407/2 Do not write outside the box 1 1 An object of mass m is accelerated from rest to a velocity v by a constant resultant force F. What is the work done on the object during this acceleration? [1 mark] A 2 Fv B Fv C mv2 D 2 2 mv 1 2 Which row describes the nature of the strong nuclear force between two nucleons at separations of 0.25 fm, 2.0 fm and 8.0 fm? [1 mark] At a separation of 0.25 fm At a separation of 2.0 fm At a separation of 8.0 fm A attractive repulsive negligible B repulsive attractive attractive C negligible repulsive attractive D repulsive attractive negligible 21 *21* Turn over ► IB/M/Jun21/7407/2 Do not write outside the box 1 3 Some energy levels of a lithium atom are shown below. A free electron with kinetic energy 6.0 × 10−19 J collides with a stationary lithium atom in its n = 1 energy level. The lithium atom is excited to the n = 2 energy level. What is the kinetic energy of the free electron after the collision? [1 mark] A 0.3 × 10−19 J B 2.6 × 10−19 J C 3.1 × 10−19 J D 5.7 × 10−19 J 1 4 What are the products when a free neutron decays? [1 mark] A p + e− + ev B p + e+ + ev C p + e− + ev D p + e+ + ev 22 *22* IB/M/Jun21/7407/2 Do not write outside the box 1 5 A progressive wave travels along a rope in the direction M to N. X marks a point on the rope. The wave has a frequency of 5.0 Hz, a wavelength of 1.0 m and an amplitude of 0.20 m. Where will X be after 0.15 s? [1 mark] A below MN by 0.20 m B above MN by 0.20 m C nearer N by 0.15 m D nearer N by 0.75 m 1 6 What is true for an inelastic collision between two isolated objects? [1 mark] A Both total momentum and total kinetic energy are conserved. B Neither total momentum nor total kinetic energy is conserved. C Only total kinetic energy is conserved. D Only total momentum is conserved. 25 *25* Turn over ► IB/M/Jun21/7407/2 Do not write outside the box 1 9 In a Young’s double-slit experiment, monochromatic light is incident on two narrow slits and the resulting interference pattern is observed on a screen. Which change decreases the fringe separation? [1 mark] A decreasing the separation between the two slits B increasing the distance between the slits and the screen C using monochromatic light of higher frequency D using monochromatic light of longer wavelength 2 0 In the circuit shown, the cell has an emf of 12 V and an internal resistance which is not negligible. When the resistance of the variable resistor is 10 Ω the voltmeter reads 10 V and the ammeter reads 1.0 A. The resistance of the variable resistor is changed to 5 Ω. What is the new reading on the ammeter? [1 mark] A 1.4 A B 1.7 A C 2.0 A D 2.4 A 26 *26* IB/M/Jun21/7407/2 Do not write outside the box 2 1 The graph shows how the maximum kinetic energy Ek(max) of photoelectrons emitted from a metal surface varies with the frequency f of the incident radiation. P is the intercept on the f axis. Q is the intercept on the Ek(max) axis. Which graph shows the variation of Ek(max) with f for a metal with a greater work function? [1 mark] A B C D A B C D 27 *27* Turn over ► IB/M/Jun21/7407/2 Do not write outside the box 2 2 P and R are uniform spheres of mass 3 kg and 4 kg respectively. P and R are joined by a rod of negligible mass. The distance between their centres is L. The centre of mass of this system is at Q. Which diagram shows the position of the centre of mass? [1 mark] A B C D A B C D Turn over for the next question 30 *30* IB/M/Jun21/7407/2 Do not write outside the box 2 6 A mass m is added to a vertical spring that is initially unextended, as shown in Diagram 1. The mass is then lowered until it hangs stationary on the spring, as shown in Diagram 2. The extension of the spring is now ΔL. Diagram 1 Diagram 2 How much energy is transferred from the mass–spring system? [1 mark] A 2 mg L∆ B mgΔL C 3 2 mg L∆ D 2mgΔL 31 *31* Turn over ► IB/M/Jun21/7407/2 Do not write outside the box Questions 27 and 28 are about three spheres X, Y and Z. The relative mass and relative diameter of each sphere are given in the table. X Y Z relative mass 1 5 1 relative diameter 1 1 5 Each sphere is dropped from rest and accelerates to its terminal speed. 2 7 What is true about the accelerations of the spheres at the instant they are released? [1 mark] A The acceleration of X is less than that of Y. B The acceleration of X is greater than that of Z. C The acceleration of X is the same as that of Y. D The acceleration of Y is less than that of Z. 2 8 What is true about the terminal speeds? [1 mark] A The terminal speed of X is greater than that of Y. B The terminal speed of X is the same as that of Y. C The terminal speed of Y is greater than that of Z. D The terminal speed of X is less than that of Z. Turn over for the next question 32 *32* IB/M/Jun21/7407/2 Do not write outside the box 2 9 The diagram shows the currents in a set of wires. What is the magnitude of the current at X? [1 mark] A zero B 2 A C 3 A D 6 A 3 0 Resistors of resistance R, R and 3R are connected as shown. What is the resistance of the arrangement? [1 mark] A 3 7 R B 7 3 R C 5 6 R D 6 5 R 35 *35* Turn over ► IB/M/Jun21/7407/2 Do not write outside the box 3 3 Measurements are taken to determine the resistivity of a uniform metal wire. The table shows the quantities measured and their percentage uncertainties. Quantity Percentage uncertainty potential difference across wire 0.3% current in wire 5.0% diameter of wire 4.0% length of wire 0.2% What is the percentage uncertainty in the calculated value for the resistivity of the metal of the wire? [1 mark] A 1.6% B 9.5% C 13.5% D 21.5% 3 4 Superconductors are used to [1 mark] A increase the strength of electricity cables. B make light dependent resistors. C produce strong magnetic fields. D increase the rate of heat energy transfer. Turn over for the next question 36 *36* IB/M/Jun21/7407/2 Do not write outside the box 3 5 Which shows the classification of particles? [1 mark] A B C D A B C D END OF QUESTIONS 30 37 *37* IB/M/Jun21/7407/2 Do not write outside the box There are no questions printed on this page DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED