Question map
Not attempted Correct Incorrect ★ Bookmarked
Loading…
Q128 (IAS/1998) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Electricity and magnetism Answer Verified

Assertion (A) : The temperature of a metal wire rises when an electric current is passed through it. Reason (R) : Collision of metal atoms with each other releases heat energy.

Result
Your answer: —  Â·  Correct: C
Explanation

Assertion is true: when current flows through a metal wire some electrical energy is dissipated as heat due to the wire’s resistance, so the wire’s temperature rises (observed for nichrome and other conductors) [1]. Reason is false as stated: heat is not produced by collisions of metal atoms with each other. Microscopically, moving conduction electrons scatter from the vibrating lattice ions (and impurities), transferring energy to the lattice and increasing ionic vibrational energy — i.e., temperature rises due to electron–lattice (electron–ion) collisions, not atom–atom collisions. This electron–lattice energy transfer underlies Joule heating and the P = I^2R heating behavior.

Sources

  1. [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 4: Electricity: Magnetic and Heating Effects > Activity 4.5: Let us observe > p. 53
How others answered
Each bar shows the % of students who chose that option. Green bar = correct answer, blue outline = your choice.
Community Performance
Out of everyone who attempted this question.
50%
got it right
✓ Thank you! We'll review this.

SIMILAR QUESTIONS

IAS · 2002 · Q143 Relevance score: 1.58

Assertion (A) : With the increase of temperature, the viscosity of glycerine increases. Reason (R) : Rise of temperature increases kinetic energy of molecules.

IAS · 2001 · Q116 Relevance score: 0.66

Assertion (A) : A Chemical reaction becomes faster at higher temperatures. Reason (R) : At higher temperatures, molecular motion becomes more rapid.

IAS · 2001 · Q102 Relevance score: -0.30

Assertion (A) : A piece of copper and a piece of glass are heated to the same temperature. When touched, thereafter, the copper piece appears hotter than the glass piece. Reason (R) : The density of copper is more than that of glass.

IAS · 2004 · Q72 Relevance score: -0.48

Assertion (A) : In our houses, the current in AC electricity line changes direction 60 times per second. Reason (R) : The frequency of alternating voltage supplied is 60 hertz.

NDA-I · 2016 · Q64 Relevance score: -1.08

Which one of the following statements with regard to expansion of materials due to heating is not correct ?