Question

• Resistivity of copper is lower than that of aluminum which in turn is lower

than that of constantan.

• Six wires labelled as A, B, C, D, E, F have designed as per the following

parameters:

Wire Length Diameter Material Resistance

A l 2d Aluminium R1

B 2l d/2 Constantan R2

C 3l d/2 Constantan R3D l/2 3d Copper R4

E 2l 2d Aluminium R5

F l/2 4d Copper R6

Answer the following questions from 9(i) to 9(iv) using the above data. Each

question carry 1 mark.

a) Which of the wires has maximum resistance and why?

b) Which of the wires has minimum resistance and why?

c) Arrange R1, R3 and R5 in ascending order of their values. Justify your answer.

d) Nichrome is used for making heating elements of heaters, toasters, electric

iron, etc. Why​

Answer 1

(a) Wire C has maximum resistance because it has maximum length, Ieast thickness and highest resistivity. (b) Wire F has the minimum resistance since it has least length, maximum thickness and least

Answer 2

Explanation:

here's all the values of the resistances

a) c

b) F

c) R1 < R2 < R3

d) because it has high resistance and a high melting point and also it does not oxidises quickly