Question

ans,

9.1	L = 0.848 m

please answer in details i need help

Question 9 - M2 (11 marks) An incandescent light bulb is basically a resistor in an electrical circuit. The Tungsten wire filament acts as the resistor. Consider you connect an 60 Watt bulb to a 240V mains household electricity supply. 9.1) (4 marks) If the Tungsten filament is constrained to be of 15um diameter, how long does the Tungsten wire need to be to make the filament? 9.2) (2 marks) On a single plot of resistivity on the y-axis versus temperature on the x-axis, sketch how you would expect the resistivity of Pure Tungsten metal to change as you change temperature. The x-axis should start at 0K. Both axes should be drawn with linear scales. 9.3) (1 mark) Often the Tungsten used in incandescent light bulbs is not Pure Tungsten, but Tungsten containing a few percent Aluminium atoms where the Aluminium atoms substitute exactly for the Tungsten atoms on the atomic lattice of Tungsten. Add to the plot in (Q10.2) a sketch of the temperature dependence of the resistivity you expect for this Tungsten-Aluminium alloy containing a few percent Aluminium. Add to the plot in Q9.2 9.4) (2 marks) If your Tungsten-Aluminium resistivity curve differs from that of Pure Tungsten explain the differences in terms of the underlying physical mechanisms. 9.5) (2 marks) The first incandescent filaments used charcoal as the filament. Charcoal is essentially Pure carbon, which is covalently bonded in the same tetragonal way that Silicon is bonded. Add to your plot of resistivity versus temperature in (Q9.2) a sketch for the temperature dependence of the resistivity of charcoal. Add to the plot in Q9.2

Answer 1

Given value of L = 0.848m is not correct, the one I calculated is different and right one and value is -

haVe Paves A 2 2.40 6 G Resistivity o meto

diometer > 이 2 TTす 2

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