RI 2020 Y5 H2 Physics TP Section B QP

© Raffles Institution [Turn over Name: ( ) CT Group: 21S0 RAFFLES INSTITUTION 2020 YEAR 5 TERM 3 TIMED PRACTICE 24 June 2020 H2 PHYSICS RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INST ITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES Section B INSTRUCTIONS TO CANDIDATES Write your name, index number and CT Group. For Examiner’s Use Write your answers to Section B in the spaces provided on the question paper. Section A MCQ / 11 Section B 12 / 11 13 / 11 14 / 12 15 / 12 16 / 11 17 / 12 Deductions Total / 80 This document consists of 15 printed pages.

2 © Raffles Institution 12 (a) A student drains the water from a fully filled rectangular water tank of length L, width w and height h into a drain by using a tube of cross-sectional area A, as shown in Fig. 12.1. The drain is located at a vertical distance d below the surface of the water in the tank. (i) The student proposed that the time t taken to empty a fully filled tank is given by 2 Lwht A gd ××= where g is the acceleration of free fall. Show that the equation is homogeneous. [2] (ii) State two ways why the equation in (i) may be physically incorrect, even though it is homogeneous. 1. 2. [2] h L w d drain tube Fig. 12.1

3 © Raffles Institution [Turn over (b) A wire of uniform circular cross -section has diameter d and length L. When a potential difference V is applied across the ends of the wire, a current I flows through the wire. The resistivity ρ of the material of the wire is given by the expression 2 4 dV L π= Iρ In one particular experiment, the following measurements are made. d = (0.32 ± 0.01) mm L = (50.0 ± 0.1) cm V = (1.60 ± 0.02) V I = (0.23 ± 0.04) A (i) Suggest an instrument that was used to measure d. [1] (ii) Calculate the value of ρ. ρ = Ω m [2] (iii) Calculate the actual uncertainty in ρ. actual uncertainty in ρ = Ω m [2] (iv) State the value of ρ and its actual uncertainty to the appropriate number of significant figures. ρ = ± Ω m [1] (v) Suggest an improvement that ca