question_answer

        Read the following information (a) Resistivity of copper is lower than that of aluminium which, in turn, is lower than that of constantan. (b) Six wires labelled as A, B, C, D, E and F have been designed as per the following parameters.

Wire	Length	Diameter	Materials	Resistances
A		2d	Aluminium
B		d/2	Constantan
C		d/2	Constantan
D		3d	Copper
E		2d	Aluminium
F		4d	Copper

Answer the following questions using the above data (a) Which of the wires has maximum resistance and why? (b) Which of the wires has minimum resistance and why? (c) Arrange  and  in ascending order of their values. Justify your answer.

Answer:

                  (a) Wire C has maximum resistance because it has maximum length, least thickness and highest resistivity.                                             (1) (b) Wire F has the minimum resistance since it has least length, maximum thickness and least resistivity (c)  (using relation and  comparison).                                                      (1)