
Heat current is maximum in which of the following (rods are of identical dimension)
A. Copper
B. Copper steel
C. Steel copper
D. Steel
Answer
162k+ views
Hint: Thermal conductivity is a measure of the capacity of a substance to conduct heat. Low thermal conductivity materials will transmit heat at a slower pace than high thermal conductivity materials. Metals that have high thermal conductivity are extremely effective at transferring heat, whereas insulating materials have low thermal conductivity. These high thermal conductivity materials are commonly utilized in heat sink applications, where low thermal conductivity materials are used as thermal insulation.
Complete step by step solution:
As we know the formula for the heat current, as,
\[\dfrac{{dQ}}{{dt}} \propto K\]
That is, the rate of change of heat is directly proportional to the thermal conductivity. As the thermal conductivity of copper is found to be maximum, then, the heat current will also be maximum in copper. The thermal resistance of copper is lesser than the thermal resistance of steel.
The thermal conductivities of typical materials range from 4-8 orders of magnitude. Pure metals have high thermal conductivity, whereas gases have low thermal conductivity. For example, copper has a heat conductivity of 10K times that of air under normal circumstances.
And also, the allotropes of carbon, namely graphite and diamond have the greatest thermal conductivities at room temperature. Therefore, the thermal resistance is minimum so heat current is maximum in copper.
Hence, option A is the correct answer.
Note:Lattice vibrations are the reasons for thermal conductivity in non-metals. The fluctuation in temperature (increase or decrease) does not significantly affect the mean free path of phonons, which means that the variation in thermal conductivities of non-metals is minimal.
Complete step by step solution:
As we know the formula for the heat current, as,
\[\dfrac{{dQ}}{{dt}} \propto K\]
That is, the rate of change of heat is directly proportional to the thermal conductivity. As the thermal conductivity of copper is found to be maximum, then, the heat current will also be maximum in copper. The thermal resistance of copper is lesser than the thermal resistance of steel.
The thermal conductivities of typical materials range from 4-8 orders of magnitude. Pure metals have high thermal conductivity, whereas gases have low thermal conductivity. For example, copper has a heat conductivity of 10K times that of air under normal circumstances.
And also, the allotropes of carbon, namely graphite and diamond have the greatest thermal conductivities at room temperature. Therefore, the thermal resistance is minimum so heat current is maximum in copper.
Hence, option A is the correct answer.
Note:Lattice vibrations are the reasons for thermal conductivity in non-metals. The fluctuation in temperature (increase or decrease) does not significantly affect the mean free path of phonons, which means that the variation in thermal conductivities of non-metals is minimal.
Recently Updated Pages
A steel rail of length 5m and area of cross section class 11 physics JEE_Main

At which height is gravity zero class 11 physics JEE_Main

A nucleus of mass m + Delta m is at rest and decays class 11 physics JEE_MAIN

A wave is travelling along a string At an instant the class 11 physics JEE_Main

The length of a conductor is halved its conductivity class 11 physics JEE_Main

Two billiard balls of the same size and mass are in class 11 physics JEE_Main

Trending doubts
JEE Main 2025 Session 2: Application Form (Out), Exam Dates (Released), Eligibility, & More

JEE Main 2025: Derivation of Equation of Trajectory in Physics

Electric Field Due to Uniformly Charged Ring for JEE Main 2025 - Formula and Derivation

Displacement-Time Graph and Velocity-Time Graph for JEE

Class 11 JEE Main Physics Mock Test 2025

Differentiate between audible and inaudible sounds class 11 physics JEE_Main

Other Pages
JEE Advanced Marks vs Ranks 2025: Understanding Category-wise Qualifying Marks and Previous Year Cut-offs

JEE Advanced 2025: Dates, Registration, Syllabus, Eligibility Criteria and More

Units and Measurements Class 11 Notes: CBSE Physics Chapter 1

Motion in a Straight Line Class 11 Notes: CBSE Physics Chapter 2

NCERT Solutions for Class 11 Physics Chapter 1 Units and Measurements

NCERT Solutions for Class 11 Physics Chapter 2 Motion In A Straight Line
