1.7.1 · D1Temperature — thermal equilibrium, thermometers, scales
Temperature ek single number hai jo do touching objects share karte hain jab unke beech heat flow band ho jaati hai. Parent page pe baaki sab cheezein — thermometers, scales, absolute zero — sirf us shared number ko measure aur label karne ki machinery hain.
Ye page ek toolbox hai. Parent note padhne se pehle, tumhe har wo symbol bina rukke padhna aana chahiye jo wo likhta hai. Neeche, har symbol ko teen cheezein milti hain: plain words mein matlab , jo picture wo represent karta hai , aur kyun topic uske bina aage nahi badh sakta . Ye is tarah order mein hain ki har ek sirf pehle waalon pe lean karta hai.
Definition Heat (word, koi letter se pehle)Heat wo energy hai jo move karti hai kyunki ek cheez doosri se zyada hot hoti hai. Ye energy hai transit mein — jaise paani pipe mein flow karta hai, na ki tank mein baitha hota hai. Poori kahani ke liye Heat and Internal Energy dekho; yahan hume sirf flow ki picture chahiye.
Pehla figure dekho. Do blocks touch kar rahe hain. Wavy red arrows energy ko hot block se cold block mein jaate dikhate hain. Arrows waqt ke saath chhote hote hain. Jab wo gayab ho jaate hain, flow band ho gayi.
Ye "arrows vanish" wala moment hi poora reason hai ki temperature exist karta hai. Us image ko pakad ke rakho — neeche har symbol usi ko decorate karta hai.
System bas "wo object jo humne dekhna choose kiya" hai — ek block, ek cup of water, ek balloon of gas. Baaki sab surroundings hain.
Picture: jis cheez ki tumhe parwah hai uske around ek dotted box banao. Andar = system. Bahar = surroundings.
Definition Macroscopic propertyEk macroscopic property wo cheez hai jo tum poore system ke baare mein individual atoms dekhe bina measure kar sakte ho: uska pressure , uska volume , uski length , uska colour, uski electrical resistance.
Topic ko kyun chahiye: parent note mein "their properties stop changing" ka matlab hai ye numbers ka rukna. Bina kisi measurable property ke, "kuch nahi badlta" ek feeling hoti, physics nahi.
In mein se har ek ek letter hai jo ek aisi number represent karta hai jo tum gauge pe padh sakte ho.
P V L
P pressure : ek gas apne container ki walls pe bahar ki taraf kitna zor se dhakelta hai, pascals mein (Pa P V volume : system kitni jagah fill karta hai, m 3 L length : jaise ek glass tube mein mercury thread ki height. Picture: ek red line ruler pe chadh rahi hai.
Har ek thermometric property ka candidate hai: ek aisi number jo reliably shift hoti hai jab hotness shift hoti hai. Parent note isko generally X
Intuition Unhe ek single stand-in nameX koi bhi property lo aur usse thermometer banao" bina length ke liye, phir pressure ke liye, phir resistance ke liye argument repeat kiye. To wo ek general symbol X X = P X = L
Ye topic ka star hai, isliye isko apna figure milta hai.
T t C t F
t C Celsius scale pe temperature (°C): ice 0 100 t F Fahrenheit scale pe temperature (°F): ice 32 212 T Kelvin (absolute) scale pe temperature (K): ice 273.15
Picture: teen thermometers side by side, same physical bath, glass pe teen alag numbers printed hain (figure dekho). Mercury same height pe hai — sirf printed numbers differ karte hain.
Intuition Topic teen scales ki kyun baat karta haiEk scale bas zero kahan rakhte ho aur ek step kitna bada hota hai hai. Celsius ka zero ice pe hai; Kelvin ka zero absolute coldest pe. Kyunki ye same physical cheez measure karte hain, inke beech convert karna pure arithmetic hai — parent ke conversion formulas yahi karte hain.
t t Yahan nahi. Is topic pe t C t F temperatures hain; capital T
0 tr C F chhota sa label hai jo kehta hai "kaun sa particular value." Ye kabhi main letter ka matlab nahi badalta.
P 0 T tr P tr X tr triple point pe values ("tr") — Kelvin scale ka single anchor point, 273.16 K t C t F Celsius / Fahrenheit scale pe temperature.
Δ Δ T T final value minus initial value : kitna move kiya, kahan hai nahi.
Picture: thermometer pe do dots; Δ Topic ko kyun chahiye: ek reading convert karna aur ek change convert karna alag rules use karta hai — origin shift (+ 32 + 273.15 Δ
Parent likhta hai T ( X ) = a X + b
a b T X
a slope : X T b intercept : jab X = 0 T
Do unknowns (a b do known points chahiye. Yahi reason hai ki parent do fixed points (ice + steam) use karta hai.
α P = P 0 ( 1 + α t C ) α ≈ 273.15 1 ° C − 1 ek gas apne ice-point pressure ka kitna bada fraction har degree Celsius pe gain karta hai .
Picture: pressure-vs-Celsius line ki slope, starting pressure ke fraction ke roop mein likhi gayi. Us line ko peeche follow karo jab tak P 0 − 273.15 ° C Ideal Gas Law disguise mein chhupa hua hai.)
∝ T ∝ X X T b = 0 Picture: pichle figure ki special line jo ( 0 , 0 ) T = T tr X / X tr
Definition "same temperature"= thermal equilibrium mein hote hain, hum likhte hain ki unka T Zeroth Law of Thermodynamics hi hai jo guarantee karta hai ki ye "equals" real equality ki tarah behave kare (agar A = C B = C A = B
Heat as energy in transit
Thermal equilibrium: flow stops
System and its macro properties P V L
Zeroth Law makes equals real
Temperature: one shared number T
Two fixed points ice and steam
Scales tC tF T and conversions
Worked example Same bath ko teen scales pe padhnaEk bath t C = 25 ° C t F = 5 9 ( 25 ) + 32 = 45 + 32 = 77 ° F T = 25 + 273.15 = 298.15 K Kyun: mercury ki height ek physical fact hai; har scale bas uske liye ek alag number print karta hai. Same physical cheez, teen labels — ye section 3 action mein hai.
Right-hand side cover karo aur reveal karne se pehle har answer zor se bolo.
Δ T T Change (final minus initial); T Δ T
T = a X + b a b a b T X = 0
Linear scale ke liye exactly do fixed points kyun chahiye? Do unknowns (a , b
Thermometric property X Koi bhi measurable macroscopic property jo hotness ke saath smoothly aur reproducibly vary karti ho — length, pressure, resistance, gas volume.
∝ Ye origin se guzarti hai, isliye intercept b = 0 X T
t C Is topic pe scale subscript ke saath t temperature hai; capital T
Subscript "tr" ka kya matlab hai? "Water ka triple point" — 273.16 K
Thermal equilibrium ko kaun sa physical event define karta hai? Do touching systems ke beech net heat flow band ho gayi ho aur unki macroscopic properties ab nahi badal rahi hoon.
P = P 0 ( 1 + α t C ) α Gas pressure mein har degree Celsius pe fractional rise; uski line ko P = 0
