Physics class 10 Federal Board chapter 10 Heat capacity specific heat modes of heat transfer conduction convection radiation

ls -la /tmp/workspace/ 2>/dev/null || mkdir -p /tmp/workspace/physics-ch10 && echo "Directory ready"

mkdir -p /tmp/workspace/physics-ch10 && python3 << 'EOF' from reportlab.lib.pagesizes import A4 from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle from reportlab.lib.units import cm from reportlab.lib import colors from reportlab.platypus import SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle, HRFlowable from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_JUSTIFY doc = SimpleDocTemplate( "/tmp/workspace/physics-ch10/Physics_Ch10_Heat_QA.pdf", pagesize=A4, rightMargin=2*cm, leftMargin=2*cm, topMargin=2*cm, bottomMargin=2*cm ) styles = getSampleStyleSheet() # Custom styles title_style = ParagraphStyle( 'CustomTitle', parent=styles['Title'], fontSize=18, textColor=colors.HexColor('#1a237e'), spaceAfter=6, alignment=TA_CENTER, fontName='Helvetica-Bold' ) subtitle_style = ParagraphStyle( 'Subtitle', parent=styles['Normal'], fontSize=12, textColor=colors.HexColor('#283593'), spaceAfter=4, alignment=TA_CENTER, fontName='Helvetica' ) section_style = ParagraphStyle( 'Section', parent=styles['Heading1'], fontSize=14, textColor=colors.white, backColor=colors.HexColor('#1565C0'), spaceBefore=14, spaceAfter=8, leftIndent=6, rightIndent=6, borderPad=6, fontName='Helvetica-Bold' ) q_style = ParagraphStyle( 'Question', parent=styles['Normal'], fontSize=11, textColor=colors.HexColor('#b71c1c'), spaceBefore=10, spaceAfter=3, leftIndent=10, fontName='Helvetica-Bold' ) a_style = ParagraphStyle( 'Answer', parent=styles['Normal'], fontSize=10.5, textColor=colors.HexColor('#1b5e20'), spaceBefore=2, spaceAfter=6, leftIndent=20, leading=15, alignment=TA_JUSTIFY, fontName='Helvetica' ) note_style = ParagraphStyle( 'Note', parent=styles['Normal'], fontSize=9, textColor=colors.HexColor('#5d4037'), spaceBefore=2, spaceAfter=4, leftIndent=20, fontName='Helvetica-Oblique' ) story = [] # ── HEADER ────────────────────────────────────────────────────────────────── story.append(Spacer(1, 0.3*cm)) story.append(Paragraph("Physics – Class 10 | Federal Board", subtitle_style)) story.append(Paragraph("Chapter 10: Heat", title_style)) story.append(Paragraph("Heat Capacity &amp; Modes of Heat Transfer", subtitle_style)) story.append(Paragraph("10 Questions &amp; Answers from Each Section", subtitle_style)) story.append(HRFlowable(width="100%", thickness=2, color=colors.HexColor('#1565C0'), spaceAfter=12)) # ══════════════════════════════════════════════════════════════════════════════ # SECTION 1: HEAT CAPACITY # ══════════════════════════════════════════════════════════════════════════════ story.append(Paragraph(" SECTION 1: HEAT CAPACITY", section_style)) heat_capacity_qa = [ ( "Q1. What is meant by thermal capacity (heat capacity) of a body?", "Ans: The thermal capacity (heat capacity) of a body is the amount of heat energy required to raise the temperature of the whole body by 1°C (or 1 K). " "It depends on the mass of the body and the material it is made of. " "SI unit: J/K (joules per kelvin).", "Formula: C = Q / ΔT, where Q is heat absorbed and ΔT is the rise in temperature." ), ( "Q2. Define specific heat capacity and state its SI unit.", "Ans: Specific heat capacity (c) is the amount of heat energy required to raise the temperature of 1 kg of a substance by 1°C (or 1 K). " "It is a property of the material, not of the object's size or mass. " "SI unit: J kg⁻¹ K⁻¹.", "Formula: c = Q / (m × ΔT)" ), ( "Q3. Write the formula relating heat, mass, specific heat capacity, and temperature change.", "Ans: Q = m × c × ΔT\n" "Where: Q = heat energy absorbed or released (J)\n" " m = mass of the substance (kg)\n" " c = specific heat capacity (J kg⁻¹ K⁻¹)\n" " ΔT = change in temperature (K or °C)", "" ), ( "Q4. Why does water have a high specific heat capacity, and what is its practical importance?", "Ans: Water has a high specific heat capacity of 4200 J kg⁻¹ K⁻¹ because of strong hydrogen bonding between its molecules, which requires more energy to break. " "Practical importance: (i) Water is used as a coolant in car radiators and industrial engines. " "(ii) Coastal areas have moderate climates because sea water heats up and cools down slowly. " "(iii) The human body (which is ~70% water) maintains a stable internal temperature.", "" ), ( "Q5. How much heat is required to raise the temperature of 2 kg of water from 20°C to 70°C? " "(Specific heat of water = 4200 J kg⁻¹ K⁻¹)", "Ans: Given: m = 2 kg, c = 4200 J kg⁻¹ K⁻¹, ΔT = 70 – 20 = 50°C\n" "Q = m × c × ΔT\n" "Q = 2 × 4200 × 50\n" "Q = 420,000 J = 420 kJ", "" ), ( "Q6. What is the difference between heat and temperature?", "Ans: Heat is a form of energy that flows from a hotter body to a cooler body due to a temperature difference; it is measured in joules (J). " "Temperature is a measure of the average kinetic energy of the molecules of a body; it is measured in Celsius (°C) or Kelvin (K). " "Key difference: Two bodies can have the same temperature but different amounts of heat (e.g., a large pot of warm water vs. a small cup of boiling water).", "" ), ( "Q7. What is the principle of calorimetry? How is it used to find specific heat capacity?", "Ans: Principle of Calorimetry: Heat lost by the hot body = Heat gained by the cold body (when no heat is lost to the surroundings). " "m₁ × c₁ × (T₁ – Tf) = m₂ × c₂ × (Tf – T₂)\n" "Where T₁ > Tf > T₂. By measuring the masses, initial temperatures, and the final mixed temperature, the unknown specific heat (c₂) of a substance can be calculated.", "" ), ( "Q8. Define latent heat. Distinguish between latent heat of fusion and latent heat of vaporisation.", "Ans: Latent heat is the heat energy absorbed or released by a substance during a change of state (phase change) without any change in temperature.\n" "• Latent heat of fusion (Lf): Heat required to convert 1 kg of solid to liquid at its melting point. For ice: Lf = 3.36 × 10⁵ J/kg.\n" "• Latent heat of vaporisation (Lv): Heat required to convert 1 kg of liquid to gas at its boiling point. For water: Lv = 2.26 × 10⁶ J/kg.", "" ), ( "Q9. Why does a burn from steam at 100°C cause more damage than one from water at 100°C?", "Ans: When steam at 100°C condenses on skin, it releases its latent heat of vaporisation (2.26 × 10⁶ J/kg) in addition to the heat it gives off as it cools from 100°C to body temperature. " "Water at 100°C only gives off sensible heat as it cools down. " "Therefore, steam transfers far more total heat energy to the skin, causing more severe burns.", "" ), ( "Q10. Describe the working principle of a calorimeter.", "Ans: A calorimeter is a well-insulated container (usually made of polished copper or aluminium) used to measure heat exchange. " "Working principle: The inner container is isolated from the surroundings by an insulating outer jacket so that heat loss is minimised. " "A known hot substance is dropped into cold water inside the calorimeter. " "By applying the principle of calorimetry (heat lost = heat gained), the specific heat capacity of the unknown substance is determined. " "The polished surface reduces radiation losses.", "" ), ] for i, (q, a, note) in enumerate(heat_capacity_qa): story.append(Paragraph(q, q_style)) for line in a.split('\n'): story.append(Paragraph(line.strip(), a_style)) if note: story.append(Paragraph(note, note_style)) if i < len(heat_capacity_qa) - 1: story.append(HRFlowable(width="90%", thickness=0.5, color=colors.HexColor('#bbdefb'), spaceAfter=2)) # ══════════════════════════════════════════════════════════════════════════════ # SECTION 2: MODES OF HEAT TRANSFER # ══════════════════════════════════════════════════════════════════════════════ story.append(Spacer(1, 0.5*cm)) story.append(Paragraph(" SECTION 2: MODES OF HEAT TRANSFER", section_style)) modes_qa = [ ( "Q1. What are the three modes of heat transfer? Briefly define each.", "Ans: The three modes of heat transfer are:\n" "1. Conduction: Transfer of heat through a solid material by direct contact of molecules, without any bulk movement of the material.\n" "2. Convection: Transfer of heat in fluids (liquids or gases) by the actual movement (bulk flow) of the heated fluid molecules.\n" "3. Radiation: Transfer of heat energy in the form of electromagnetic waves (infrared radiation), which requires no medium.", "" ), ( "Q2. Explain the process of heat conduction in solids with a molecular explanation.", "Ans: In conduction, when one end of a solid rod is heated, the molecules at that end gain kinetic energy and vibrate more rapidly. " "These fast-vibrating molecules transfer energy to adjacent slower-vibrating molecules through collision and interaction, " "without changing their mean positions. This process continues along the rod until heat reaches the cooler end. " "Metals are good conductors because free electrons also carry thermal energy quickly through the lattice.", "" ), ( "Q3. Define thermal conductivity. What are good conductors and poor conductors of heat?", "Ans: Thermal conductivity (k) is a measure of a material's ability to conduct heat. " "It is defined as the heat flow per unit time through a unit area of a material per unit temperature gradient. " "SI unit: W m⁻¹ K⁻¹.\n" "Good conductors: Silver, copper, aluminium (metals) – used in cooking utensils, heat exchangers.\n" "Poor conductors (insulators): Wood, glass, wool, air, rubber – used in handles of utensils, building insulation.", "" ), ( "Q4. Explain convection currents in liquids with an example.", "Ans: When a liquid is heated from below (e.g., heating water in a beaker), the water at the bottom becomes warm, expands, and becomes less dense. " "It rises upward, while the cooler, denser water from the top sinks to the bottom to take its place. " "This circular movement of fluid is called a convection current. " "Example: Sea breezes are caused by convection – land heats up faster than sea during the day, hot air over land rises, and cooler sea air moves in to fill the space.", "" ), ( "Q5. Why are metals good conductors of heat but non-metals are poor conductors?", "Ans: Metals are good conductors because they have a large number of free electrons. " "These free electrons move rapidly through the metal lattice and transfer kinetic energy quickly from hotter regions to cooler regions. " "Non-metals (like wood or plastic) do not have free electrons; heat is transferred only through slow molecular vibrations, making them poor conductors (insulators).", "" ), ( "Q6. What is radiation? How does it differ from conduction and convection?", "Ans: Radiation is the transfer of heat energy in the form of electromagnetic waves (mainly infrared rays) that travel at the speed of light. " "It does not require any material medium and can travel through a vacuum.\n" "Differences:\n" "• Conduction requires direct contact and a solid medium.\n" "• Convection requires a fluid medium and involves mass movement.\n" "• Radiation requires neither contact nor a medium; it is the only mode that works in a vacuum (e.g., heat from the Sun reaching Earth).", "" ), ( "Q7. What is a good absorber and a good emitter of radiation? Give an example.", "Ans: A good absorber is a surface that absorbs most of the radiation falling on it. " "A good emitter is a surface that radiates heat energy efficiently.\n" "Black, dull, rough surfaces are both good absorbers and good emitters of radiation.\n" "White or shiny, polished surfaces are poor absorbers and poor emitters (they reflect radiation).\n" "Example: A matt black surface heats up faster in sunlight than a shiny silver surface. " "This is why solar panels and radiators are painted black, while thermos flasks have silvered walls.", "" ), ( "Q8. Explain how a vacuum flask (thermos flask) minimises heat transfer by all three modes.", "Ans: A vacuum (thermos) flask is designed to minimise all three modes of heat transfer:\n" "• Conduction: The double-walled glass container has a vacuum between the walls, which prevents conduction (no medium for molecules to transfer energy).\n" "• Convection: The vacuum also eliminates convection since there is no fluid to carry heat.\n" "• Radiation: The inner walls of both glass layers are silvered (mirror-like), which reflects radiation back and prevents heat from being lost or gained by radiation.", "" ), ( "Q9. Why are cooking pots made of metals but their handles made of wood or plastic?", "Ans: Cooking pots are made of metals (like aluminium or steel) because metals are good conductors of heat. " "They quickly transfer heat from the flame to the food inside the pot.\n" "Handles are made of wood or plastic because these are poor conductors (thermal insulators) of heat. " "They prevent heat from conducting from the hot pot to the person's hand, ensuring safety and comfort while handling hot cookware.", "" ), ( "Q10. Give three practical applications each of conduction, convection, and radiation.", "Ans:\n" "Conduction:\n" " (i) Cooking utensils use metallic (copper/aluminium) bases for fast heat conduction.\n" " (ii) Thermal insulation in buildings uses poor conductors (fibreglass, foam) to reduce heat loss.\n" " (iii) A doctor's stethoscope metal piece feels cold because it conducts heat away from the skin.\n\n" "Convection:\n" " (i) Central heating systems use hot water convection currents to warm rooms.\n" " (ii) Sea and land breezes are formed by convection of air.\n" " (iii) Refrigerators are cooled by convection – the freezer is placed at the top so cold air sinks.\n\n" "Radiation:\n" " (i) Solar water heaters use radiation from the Sun to heat water.\n" " (ii) Infrared thermometers measure body temperature without contact via radiation.\n" " (iii) Greenhouse effect – Earth's atmosphere traps infrared radiation from the ground, keeping it warm.", "" ), ] for i, (q, a, note) in enumerate(modes_qa): story.append(Paragraph(q, q_style)) for line in a.split('\n'): if line.strip(): story.append(Paragraph(line.strip(), a_style)) if note: story.append(Paragraph(note, note_style)) if i < len(modes_qa) - 1: story.append(HRFlowable(width="90%", thickness=0.5, color=colors.HexColor('#bbdefb'), spaceAfter=2)) # ── FOOTER NOTE ───────────────────────────────────────────────────────────── story.append(Spacer(1, 0.8*cm)) story.append(HRFlowable(width="100%", thickness=1.5, color=colors.HexColor('#1565C0'), spaceAfter=6)) story.append(Paragraph( "Physics | Class 10 | Federal Board | Chapter 10: Heat | Total: 20 Q&amp;As (10 per section)", ParagraphStyle('Footer', parent=styles['Normal'], fontSize=9, textColor=colors.grey, alignment=TA_CENTER) )) doc.build(story) print("PDF created successfully!") 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