Assertion (A) : Nichrome is an alloy which is commonly used in electrical heating devices such as electric irons, toasters, etc.
Reason (R) : The resistivity of nichrome is high and its resistance decreases with increase in temperature.
Generated by claude-sonnet-4-6 · 2026-06-15 06:43 · grounding rag
Model Answer
(C) Assertion (A) is true, but Reason (R) is false.
Assertion is correct — nichrome's high resistivity and high melting point make it suitable for heating devices. However, the Reason is false: the resistance of nichrome (and alloys in general) increases with increase in temperature, not decreases.
Source: Chapter 11, Section 11.5
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Explanation
- The Assertion is directly supported by the textbook: alloys like nichrome have high resistivity and do not oxidise at high temperatures, so they are used in electric irons, toasters, etc.
- The Reason contains one correct part (high resistivity) but one wrong part: for metallic conductors and alloys, resistance increases with temperature. The textbook states "Both the resistance and resistivity of a material vary with temperature" — for metals/alloys this variation is an increase.
- Since the Reason is partially false (the key claim about resistance decreasing is wrong), option (C) is correct.