2021 AHS Physics Prelim Paper 3

1 6 Sep 2021 1 hour 50 minutes Anglican High School Secondary Four Preliminary Examination 2021 CLASS CLASS INDEX 4 Anglican High School 2021_S4_Prelim_PHY_P3 S4 ___________________________________________________________________________________ This document consists of 11 printed pages.

2 1 In this experiment, you will investigate the resistivity and the power dissipated in a length of resistance wire. You are provided with:  a length of resistance wire (W) attached to a meter rule,  a sample of resistance wire  a micrometer screw gauge  an ammeter (0 – 1 A),  a voltmeter (0 – 5 V),  a switch,  a power supply,  a fixed resistor (R2),  connecting wires,  a jockey. Set up the apparatus as shown in Fig. 1.1 (a) Measure and record d, the diameter of the sample of resistance wire. d = …………………..…… [1] (b) Calculate the cross-sectional area of the resistance wire, in m2, using the equation shown. A =  𝑑2 4 A = …………………… m2 [1] Fig. 1.1 +  jockey Anglican High School 2021_S4_Prelim_PHY_P3 [Turn over 0 cm metre rule resistance wire, W fixed resistor, R2 power supply  𝑙

3 (c) Close the switch. Place the jockey on the resistance wire so that a length 𝑙 of 0.8 m of resistance wire is connected in the circuit. Record the current I in the circuit and the potential difference V across the length of wire. I = …………………………….. V = …………………………….. [2] (d) Open the switch. (i) Calculate the resistance R of 0.8 m of the wire using the equation shown. 𝑅 = 𝑉 𝐼 R = ………………………… [1] (ii) The resistance R and the resistivity  are related by the equation 𝑅 = 𝑙 𝐴 where A is the cross-sectional area and 𝑙 is the length of the wire. Calculate the resistivity of the wire, .  = ………………………… [2] (iii) Calculate the power dissipated P in 0.8 m of the wire using the equation shown. P = I V P = ………………………… [1] (e) Repeat (c) for 𝑙 = 0.4 m. Hence determine P for 𝑙 = 0.4 m. P = ………………………… [1] (f) Using your answers to (d)(iii) and (e), explain whether the power dissipated P is directly proportional to the length 𝑙 of the wire. …………………………………………………………………………………………………………. …………………………………………………………………………………………………………. …………………………………………………………………………………………………..…. [1] [Total: 10] Anglican High School 2021_S4_Prelim_PHY_P3 [Turn over

4 2 In this experiment, you will investigate a spinning mass. You are provided with: 