Doubtclip is an AI tutor that turns any homework or exam doubt into a step-by-step whiteboard video lesson with diagrams, formulas, and voice explanation.

Which subjects and exams does it support?

It supports Physics, Chemistry, Mathematics/Calculus and related STEM doubts for school boards, JEE, NEET, and global high-school / undergrad practice.

How do I get a video solution?

Upload a photo of the question or paste the text, sign in, and Doubtclip generates a whiteboard-style explanation video you can watch and share.

Is Doubtclip available worldwide?

Yes. Doubtclip is a web app for students globally. Lessons are available in English and Hinglish.

One end of a thermally insulated rod is kept at a temperature T1 and the other at T2. The rod is composed of two sections of lengths 1 and 2 and thermal conductivities k1 and k2 respectively. The temperature at the interface of the two sections is

(k1 2 T1+k2 1 T2 ) / (k1 2+k2 1 )

(k2 2 T1+k1 1 T2 ) / (k1 1+k2 2 )

(k2 1 T1+k1 1 T2 ) / (k2 1+k1 2 )

(k1 1 T1+k2 2 T2 ) / (k1 1+k2 2 )

Thermal Properties of Matter

JEE Main level, single correct, medium

109 of 126

Question 109 of 126

One end of a thermally insulated rod is kept at a temperature $T_1$ and the other at $T_2$ . The rod is composed of two sections of lengths $\ell_1$ and $\ell_2$ and thermal conductivities $k_1$ and $k_2$ respectively. The temperature at the interface of the two sections is

Show answer and solution

Answer: (C) $\left(\mathrm{k}_1 \ell_2 \mathrm{T}_1+\mathrm{k}_2 \ell_1 \mathrm{T}_2\right) /\left(\mathrm{k}_1 \ell_2+\mathrm{k}_2 \ell_1\right)$

\frac{\left(\mathrm{T}_1-\mathrm{T}\right) \mathrm{k}_1}{\ell_1}=\frac{\left(\mathrm{T}-\mathrm{T}_2\right) \mathrm{k}_2}{\ell_2}

\mathrm{~T}=\frac{\mathrm{T}_1 \mathrm{k}_1 \ell_2+\mathrm{T}_2 \mathrm{k}_2 \ell_1}{\mathrm{k}_1 \ell_2+\mathrm{k}_2 \ell_1}

JEE Main question paper PDF

Open a shift to read the full paper on this page, or download it.

JEE Main 2025 Apr 2 Shift 1 question paper

Open Download PDF

Opening paper…

Explain it as a whiteboard videoStep-by-step, in Hinglish or English. Your first video needs no login.Solved it on paper but got it wrong?Upload a photo of your working. Mistake Doctor marks the exact line that broke.

More Physics practice

JEE Main Physics practice question on Thermal Properties of Matter (Conduction), with the answer and a step-by-step solution. Scan a question from your own book or paper to get a whiteboard video.