Verified Solution • 2025–26 Session moderate

Q10.8: NCERT Physics - Part 2 THERMAL PROPERTIES OF MATTER 10.8 Solution: A hole is drilled in a copper sheet. The diameter of the hole…

⚠️ Common Exam Traps & Conceptual Pitfalls

Students often assume a drilled hole shrinks when the surrounding material expands, but its diameter changes by ΔD = D₀αΔT exactly like any linear dimension; apply the linear expansion coefficient, not an area or inverse effect.

A hole is drilled in a copper sheet. The diameter of the hole is 4.24 cm at 27.0 �C. What is the change in the diameter of the hole when the sheet is heated to 227 �C? Coefficient of linear expansion of copper = 1.70 _ 10__ K__.

Step-by-Step Verified Solution

**Answer:** Change in diameter = 1.44×10−21.44 \times 10^{-2} cm **Step-by-Step Explanation:** The hole expands as if it were made of the same material. Using:
ΔD=D0αΔT=4.24×1.70×10−5×(227−27)\Delta D = D_0 \alpha \Delta T = 4.24 \times 1.70 \times 10^{-5} \times (227 - 27)
ΔD=4.24×1.70×10−5×200=1.44×10−2 cm\Delta D = 4.24 \times 1.70 \times 10^{-5} \times 200 = 1.44 \times 10^{-2} \text{ cm}
The new diameter is 4.24+0.0144=4.25444.24 + 0.0144 = 4.2544 cm. [citation:2]

All Questions in this Chapter

Q10.1 Q10.2 Q10.3 Q10.4 Q10.5 Q10.6 Q10.7 Q10.8 Q10.9 Q10.10 Q10.11 Q10.12 Q10.13 Q10.14 Q10.15 Q10.16 Q10.17 Q10.18 Q10.19 Q10.20

Related Learning Resources & Exam Preparation

Chapter Practice Bank
Practice all topic-wise questions from THERMAL PROPERTIES OF MATTER
Reference Textbook Solutions
Explore complete chapter exercises for NCERT Physics - Part 2
Competitive PYQ Question Bank
Browse year-wise authentic previous years' questions with solutions
Authentic CBT Mock Tests
Simulate official exam environment with live timer and percentile scoring