Assertion (A): Alloys are commonly used in electrical heating devices like electric iron and heater.

Reason (R): Resistivity of an alloy is generally higher than that of its constituent metals but the alloys have low melting points than their constituent metals.

<strong>Why the key is correct:</strong><br><ul><li><strong>Assertion (A) is true:</strong> Alloys like Nichrome are indeed commonly used in electrical heating devices such as electric irons, toasters, and heaters. This is because they have high resistivity and do not oxidise (burn) readily at high temperatures.</li><li><strong>Reason (R) is false:</strong> While the first part of the reason is true ("Resistivity of an alloy is generally higher than that of its constituent metals"), the second part ("but the alloys have low melting points than their constituent metals") is false. Alloys used in heating elements must have very high melting points so that they do not melt when they become red-hot during operation.</li></ul>Therefore, Assertion (A) is true but Reason (R) is false.<br><br><strong>Why distractors are incorrect:</strong><ul><li>Options A and B are incorrect because Reason (R) is false.</li><li>Option D is incorrect because Assertion (A) is true.</li></ul>