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Matter in Our Surroundings — Question 5

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Question 5

What type of clothes should we wear in summer?

Answer

During summer we perspire more. During evaporation of sweat the particles at the surface gain energy from the surroundings or body surface and change into vapour. The heat energy equal to the latent heat of vaporization is absorbed leaving the body cool. Cotton being a good absorber of water helps in absorbing the sweat and exposing it to the atmosphere for easy evaporation. Hence, one should wear cotton clothes in summer.

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Science | Chapter 1: Matter in Our SurroundingsWeb Content — Quick Reference

Chapter 1: Matter in Our Surroundings — Quick Reference

states of matter particle nature change of state evaporation latent heat melting boiling sublimation

Quick Revision Points

  • Matter has mass and occupies space; made of particles with spaces, motion, and attraction
  • Three states: Solid (fixed shape/volume), Liquid (fixed volume, not shape), Gas (neither fixed)
  • Melting point of ice = 0°C (273 K); Boiling point of water = 100°C (373 K)
  • Latent heat of fusion of ice = 334 J/g; Latent heat of vaporisation of water = 2260 J/g
  • Sublimation: solid → gas directly (camphor, dry ice, naphthalene)
  • Evaporation: surface phenomenon at all temperatures; causes cooling; factors: surface area, temperature, humidity, wind
  • Temperature conversion: T(K) = T(°C) + 273
Exam Tips for Chapter 1
  • Read the detailed chapter notes for complete coverage of all NCERT topics.
  • Practice all NCERT in-text and back exercise questions — they are frequently asked in exams.
  • Focus on comparison tables, diagrams, and definitions — these are high-scoring areas.
  • For numericals (if applicable), practice at least 20 problems of varying difficulty.
  • Refer to the practice question bank (200+ questions) for thorough preparation.
Related Resources
  • Detailed Notes: ch01-matter-in-our-surroundings.html
  • Practice Questions: 100+ questions with answers in 05-practice-questions/
  • Chapter Test: 30-mark test paper in 06-tests/chapter-tests-30marks/
  • Formula Sheet: Complete formula reference in 03-teacher-aid/formula-sheet.html
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