*18 The circuit diagram shows three identical resistors an…

*18 The circuit diаgrаm shоws three identicаl resistоrs and twо switches, X and Y. The battery has negligible internal resistance.   See addendum Figure 18.1   Each resistor consists of a wire of diameter 0.181 mm and length 55.0 cm. At room temperature, the resistivity of the wire is 1.10 × 10−6 Ω m.   (a) Show that the resistance of one resistor at room temperature is about 24 Ω. (3)       (b) A student suggests that the maximum power output from the resistors in this circuit will be greater than 12 W. Assess whether the student's suggestion is correct. (4)       (c) Switch X was open and switch Y was closed.   (i) Calculate the number of conduction electrons passing through the resistor every second immediately after switch Y was closed. (3) (ii) After switch Y had been closed for a few minutes, the power dissipated by the resistor decreased. Explain why. (3)   (Total for question 18 = 13 marks)