Assertion (A): Alloys are preferred over pure metals for making the heating elements of electric irons and to…

Question

Assertion (A): Alloys are preferred over pure metals for making the heating elements of electric irons and toasters.
Reason (R): Alloys have higher resistivity and do not oxidise easily at high temperatures.
(A) Both A and R are true and R is the correct explanation of A.
(B) Both A and R are true but R is not the correct explanation of A.
(C) A is true but R is false.
(D) A is false but R is true.

Accepted Answer

## Model Answer **(A) Both A and R are true and R is the correct explanation of A.** Alloys are used in heating elements because they have higher resistivity than pure metals and do not oxidise (burn) readily at high temperatures, making R the correct explanation of A. *Source: Chapter 11, Section 11.5 (Factors on which Resistance depends)* --- ## Explanation The textbook explicitly states: *"The resistivity of an alloy is generally higher than that of its constituent metals. Alloys do not oxidise (burn) readily at high temperatures. For this reason, they are commonly used in electrical heating devices, like electric iron, toasters etc."* Both properties — high resistivity (generates more heat per unit current) and resistance to oxidation — directly explain why alloys are preferred, so R correctly and completely explains A. Choose option (A).

Science (086) — AI-generated practice question