MI 2024 PU3 H2 PHYSICS PRELIM P3A QP

Class Adm No Candidate Name: This document consists of 17 printed pages and 1 blank page. [Turn over 2024 Preliminary Examination Pre-University 3 H2 PHYSICS 9749/03 Paper 3 Longer Structured Questions Section A Booklet 16 September Candidates answer on the Question Paper. 2 hours No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Do not turn over this page until you are told to do so. Write your full name, class and Adm number in the spaces at the top of this page. Write in dark blue or black pen on both sides of the paper. You may use an HB pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, glue or correction fluid. The use of an approved scientific calculator is expected, where appropriate. Section A Answer all questions. Section B Answer one question only. You are advised to spend one and half hours on Section A and half an hour on Section B. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use Section A 1 / 10 2 / 10 3 / 10 4 / 11 5 / 9 6 / 10 Section B 7 / 20 8 / 20 Presentation (overall) P3 Total /80

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4 Section A Answer all the questions in the spaces provided. 1 (a) A bar magnet is suspended from a helical spring and one end of the magnet is situated in a coil of wire, as shown in Fig. 1.1. The coil is connected in series with a switch and a resistor. The switch is opened. Fig. 1.1 The bar magnet is displaced vertically and then released. As the magnet passes through its rest position, a timer is started. The variation with time t of the vertical displacement of the magnet from its rest position is shown in Fig. 1.2. At t = 4.0 s, the switch is closed. Fig. 1.2 (i) Use Fig. 1.2 to determine the frequency of oscillation of the magnet. frequency = …………… Hz [2]

5 [Turn over (ii) State Faraday’s Law of electromagnetic induction. ………………………………………………………………………………………………… …………………………………………………………………………………………..… [1] (iii) Use the laws of electromagnetic induction to explain why the amplitude of oscillation decreases after the switch is closed. ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… …………………………………………………………………………………………..… [4] (b) The set -up in (a) is modified by suspending the magnet above the coil and adding an alternating voltage supply source in series with the coil and resistor, as shown in Fig .1.3. The frequency of the voltage source is set at 0.50 Hz. The magnet was at rest initially and starts oscillating when the switch is