Match List I with List II
| LIST I | LIST II |
| A. The standard resistance coil | I. Nickel-chromium alloy |
| B. The connecting wire | II. tin-lead alloy |
| C. The heating wire | III. copper metal |
| D. The fuse wire | IV. copper manganese nickel alloy |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → A-IV, B-III, C-I, D-II
A material is chosen for its job by its resistivity, by how much the resistivity changes with temperature, and by its melting point.
A. The standard resistance coil — this matches IV. copper manganese nickel alloy. This alloy is manganin; its resistivity changes very little with temperature, so a standard resistor made from it keeps its value.
B. The connecting wire — this matches III. copper metal. Copper has a very low resistivity, so little energy is lost in the connecting wires.
C. The heating wire — this matches I. Nickel-chromium alloy. Nichrome has a high resistivity and a high melting point, and it does not oxidise easily when red hot.
D. The fuse wire — this matches II. tin-lead alloy. A fuse must melt as soon as the current is too large, so it is made of an alloy with a low melting point.