1.7.4 · D1Specific heat capacity — calorimetry
Kisi substance ko heat karna matlab hai energy daalna taaki uske particles zyada tezi se hilne-dulne lagein , aur temperature kitni jaldi badhti hai yeh depend karta hai material par, quantity par, aur kitni energy daali gayi hai. Calorimetry kuch nahi bas seedha energy ka hisaab-kitaab hai: ek sealed cup mein, hot cheez jo bhi joule khoti hai woh cold cheez ko milti hai — koi bhi joule gum nahi hoti.
Pehle tum Q = m c Δ T har letter ka matlab kya hai aur uske peeche kaun si picture hai . Yeh page har ek ko zero se banata hai, ek aisi order mein jahan har idea pichle par tika hua hai. Agar tum Heat and Internal Energy mein pehle se mil chuke ho, yeh tumhara slow, visual refresher hai.
==Temperature T kisi substance ke particles kitni tezi se move kar rahe hain (solid mein vibrate karte hain). Jyada hot = zyada tezi se hilna. Hum ise degrees Celsius (°C) ya kelvin (K) mein measure karte hain.
Ek box of tiny balls (atoms) imagine karo. Low temperature par woh dheere se hilte hain; high temperature par woh tezi se uchhalte aur bounce karte hain. Temperature bas us average liveliness ka readout hai — nahi yeh kitna stuff hai, bas yeh hai ki har piece kitna energetic hai.
T temperature change karne ke baare mein hai energy add ya remove karke. Isliye T
Δ Δ "change in" ya "final minus initial" ke liye. Toh Δ T Δ T = T final − T initial
Ek thermometer dekho jo 20 se shuru hua aur 75 par khatam hua. Reading ek position hai; change Δ T = 75 − 20 = 55
Difference kyun, raw temperature kyun nahi?
Heat ko parwah hai ki tumne temperature ko kitna move kiya, nahi ki woh kahan se shuru hua. 10→20 tak warm karna utni hi cost karta hai jitni 90→100 (dono mein Δ T = 10 Δ T T
Common mistake "°C aur K alagΔ T Kyun sahi lagta hai: absolute-temperature formulas aur jagah hote hain.
Fix: Celsius aur kelvin scales same size step hain, bas 273.15 se shift hain. 55 °C ka gap hai hi 55 K ka gap. Difference ke liye tum koi bhi scale use kar sakte ho — shift cancel ho jaata hai.
==Mass m kitna substance hai tumhare paas, kilograms (kg) mein. Zyada mass = zyada particles heat karne hain.
Do cups of water side by side: ek mein 0.5 kg hai, doosre mein 1 kg. Bade wale mein twice as many water molecules hain — twice as many little balls jo jiggle honi hain.
m m
Q Q energy hai jo hotter jagah se cooler jagah flow karti hai sirf isliye ki temperature difference hai. Joules (J) mein measure hota hai. 1 J
Q > 0 mein flow karti hai (woh warm hota hai).Q < 0 bahar flow karti hai (woh cool hota hai).
Heat ko ek invisible fluid ki tarah socho jo hot se cold ki taraf dhalkta hai. Yeh hamesha temperature slope ke neeche jaata hai, apne aap kabhi upar nahi.
Intuition Heat vs. temperature — inhe confuse mat karoTemperature hai kitna hot (jiggling kitni tezi se). Heat hai kitni energy move hui . Ek swimming pool 30 °C par kaafi zyada heat energy hold karta hai ek 80 °C ki coffee se, even though coffee zyada hot hai — kyunki pool mein vastly more particles hain. Yeh distinction is chapter ka dil hai; Heat and Internal Energy dekho.
Q Q
Definition Specific heat capacity==Specific heat capacity c 1 kg substance ko 1 K (= 1 °C) badhane ke liye chahiye. Units: J kg − 1 K − 1
"Per kilogram per kelvin" heating ke ek standard unit ki recipe hai: ek kilo, ek degree. Water ka c ≈ 4186
c Δ T kitna aur kitna dur ; woh kuch nahi bolte kaun sa material hai. Alag-alag materials energy alag-alag store karte hain, isliye humein ek per-material constant chahiye. Woh constant, c
Definition Heat capacity (poora object)==Heat capacity C poore object ko (chahe uska mass kuch bhi ho) 1 K badhane ke liye chahiye. Units: J K − 1 nahi "per kg", kyunki mass already baked in hai:
C = m c
Chhota c material ki property). Capital C specific object ke liye hai. 3 kg copper block aur 1 kg copper block same c C
Recall Quick self-checkAgar block ko aadha kaat do, kaun sa change hoga? ::: C c
Definition Water equivalentKisi object ka ==water equivalent w paani ka mass hai jo same heat soak karta same temperature rise ke liye. Unke heat capacities ko equal set karke:
w c water = m c ⇒ w = c water m c
Trick: apne copper cup ko uske apne c
Definition Subscripts batate hainkaun sa object
Ek chhota number ya word neeche likha, jaise m 1 c water "yeh object 1 / paani ka hai" . Yeh ek name tag hai, koi mathematical operation nahi.
m 1 , c 1 , T 1 hot body ka mass, specific heat, start temperature.m 2 , c 2 , T 2 cold body ke liye wahi teen.T f final temperature.
Intuition Name tags ki zaroorat kyun haiCalorimetry do ya zyada cheezon ko mix karta hai. Labels ke bina hum nahi bata sakte ki kiska mass ya kiska temperature mean kar rahe hain. Subscript har object ki bookkeeping apne column mein rakhta hai.
Intuition Na kuch leak hota, na kuch appear hotaEk perfectly insulated cup mein, energy na banti hai na destroy hoti hai (Conservation of Energy aur First Law of Thermodynamics dekho). Isliye hot body se nikli energy ke paas jaane ki koi jagah nahi siwaaye cold body ke:
Heat lost by hot = Heat gained by cold Q = m c Δ T
Har ek padho aur reveal karne se pehle answer karne ki koshish karo. Agar koi bhi tumhe roka, uska section upar dubara padho.
Symbol Δ "Change in" — final minus initial.
Δ T T final − T initial
Kya 40 °C ka gap 40 K ke gap ke barabar hai? Haan — scales sirf ek constant offset se alag hain, isliye differences match karte hain.
Temperature T Particles kitni tezi se hil rahe hain (unki average liveliness).
Heat Q T Q T
Jab koi body cool down hoti hai toh Q Negative — energy bahar flow karti hai.
Specific heat capacity c J kg − 1 K − 1
Specific heat c Woh heat jo 1 kg substance ko 1 K badhane ke liye chahiye.
C c C = m c c
m 1 Quantity kaun se object ki hai — ek name tag.
Water equivalent w Paani ka woh mass jo same Δ T w = m c / c water
Kaun sa law "heat lost = heat gained" ko allow karta hai? Conservation of energy ek insulated system mein.
