GATE ME 2016 Set 1 — Question 25
Go beyond PYQs with Success TrackerAI-powered personalised practice and doubt support. Unlimited practice on eligible plans; AI usage limits apply.MCQ+1 / -0.33MediumCritical Radius of InsulationConductionHeat Transfer
Heat Transfer → Conduction → Critical Radius of Insulation
Last updated
Question
A plastic sleeve of outer radius covers a wire (radius ) carrying electric current. Thermal conductivity of the plastic is . The heat transfer coefficient on the outer surface of the sleeve exposed to air is . Due to the addition of the plastic cover, the heat transfer from the wire to the ambient will
Correct answer
(A) increase
Solution
The critical radius of insulation for a cylinder is given by .
Given:
The current outer radius of the sleeve is . Since , adding more insulation (increasing the radius up to ) will decrease the total thermal resistance and thus increase the heat transfer rate from the wire to the ambient.
Given:
The current outer radius of the sleeve is . Since , adding more insulation (increasing the radius up to ) will decrease the total thermal resistance and thus increase the heat transfer rate from the wire to the ambient.
Continue learning with Success Tracker
A step still unclear? Work through it with support
Use Success Tracker to ask about the reasoning, then try another GATE ME question to check your understanding.
AI-powered practice· Unlimited practice on eligible plans
- PYQs with solutions
- Attempt available previous-year questions, then compare your reasoning with the worked solution. Coverage varies by stream.
- Practice that adapts
- Choose a topic, work on weaker areas and bookmark questions to revisit. Your attempts feed your progress tracking.
- AI doubt support
- Ask follow-up questions about a step or concept while practising, instead of stopping at the final answer.
Unlimited practice is available on eligible plans. Free practice and AI usage have limits; check the current plan allowances before choosing.
This page stays readable without an account. AI responses can be wrong; check them against the solution and source material.
More questions on Conduction
2026 Set 1 Q27A quiescent fluid at temperature is confined between two vertical parallel plates. While…2026 Set 1 Q35A sphere of radius 5 mm is initially in equilibrium at 400 in a furnace. It is…2026 Set 1 Q43A very long fin of a uniform square cross-section is replaced by another very long fin of a uniform…2026 Set 1 Q54Two rectangular surfaces both having area are placed perpendicular to each other…2026 Set 1 Q55Convective heat transfer coefficients for Fluid 1 and Fluid 2 in a heat exchanger, as shown in the…