Dokar Farko ta Kayan Thermodynamics
Tsarin Thermodynamic
Zafi (Q) makamashi ne da ke motsawa daga abu ɗaya zuwa wani saboda bambancin zafin jiki. Dangane da tsarin da muhalli, ana iya cewa zafi makamashi ne da ke motsawa daga tsarin zuwa muhalli ko makamashin da ke motsawa daga muhalli zuwa tsarin saboda bambancin zafin jiki. Idan zafin tsarin ya fi zafin muhalli, zafi zai gudana daga tsarin zuwa muhalli. Akasin haka, idan zafin muhalli ya fi zafin tsarin girma, zafi zai gudana daga muhalli zuwa tsarin.
Idan zafi (Q) yana da alaƙa da canja wurin makamashi saboda bambancin zafin jiki, to Work (W) yana da alaƙa da canja wurin makamashi da ke faruwa ta hanyar injiniya. Misali, idan tsarin yana aiki akan muhalli, to makamashi zai canza ta atomatik daga tsarin zuwa muhalli. Akasin haka, idan muhalli yana aiki akan tsarin, to makamashi zai canza daga muhalli zuwa tsarin.
Misali mai sauƙi na canja wurin makamashi tsakanin tsarin da kewayensa wanda ya shafi zafi da aiki shine tururin zafi da ke turawa a kan murfin tukunya. Kasancewar zafi yana sa tsarin (tururi) ya tura murfin tukunya (tururin yana aiki akan muhalli). Wannan misali ɗaya ne na canji a yanayin tsarin saboda canja wurin makamashi tsakanin tsarin da kewayensa. Akwai wasu misalai da yawa. Canje-canje a yanayin tsarin saboda canja wurin makamashi tsakanin tsarin da kewayensa wanda ya shafi zafi da aiki ana kiransa da tsarin thermodynamic.
Makamashin Ciki da Dokar Farko ta Thermodynamics
Makamashin ciki (U) na tsarin shine jimlar dukkan kuzarin motsi na ƙwayoyin halitta a cikin tsarin, tare da jimlar dukkan kuzarin da ke tasowa daga hulɗar da ke tsakanin ƙwayoyin halitta a cikin tsarin. Muna tsammanin idan zafi ya gudana daga kewaye zuwa tsarin (tsarin yana karɓar makamashi), makamashin ciki na tsarin yana ƙaruwa… Akasin haka, idan tsarin yayi aiki akan muhalli (tsarin yana fitar da makamashi), makamashin ciki na tsarin yana raguwa.
Saboda haka, bisa ga ƙa'idar kiyaye makamashi, za a iya kammala da cewa canjin makamashi a cikin tsarin = Zafi da aka ƙara wa tsarin (tsarin yana karɓar makamashi) - Aikin da tsarin ya yi (tsarin yana fitar da makamashi). A lissafi:
Wannan lissafi ya shafi tsarin rufewa (tsarin rufewa tsari ne wanda ke ba da damar musayar makamashi kawai tsakanin tsarin da muhalli). Ga tsarin rufewa da aka keɓe, babu wani kuzari da ke shiga ko fita daga tsarin, saboda haka, canjin makamashin ciki = 0.
Wannan lissafi kuma ya shafi tsarin buɗewa idan muka yi la'akari da canje-canje a cikin makamashi a cikin tsarin saboda ƙari da rage adadin abu (Tsarin buɗewa tsari ne wanda ke ba da damar musayar abu da makamashi tsakanin tsarin da muhalli). An tsara dokar thermodynamics ta farko a ƙarni na sha tara, bayan an fahimci zafi a matsayin makamashin da aka canja saboda bambancin zafin jiki.
Makamashin ciki adadi ne da ke bayyana yanayin ƙaramin tsarin. Ba za a iya tantance adadin da ke bayyana yanayin ƙaramin tsarin ba (makamashin ciki) kai tsaye. Abin da muke nazari a cikin Dokar Farko ta Thermodynamics shine kawai canjin makamashin ciki. Ana iya tantance canje-canje a cikin makamashin ciki saboda kuzarin da aka ƙara wa tsarin da kuma kuzarin da tsarin ya fitar a cikin nau'in zafi da aiki. Akasin haka, adadin da ke bayyana yanayin babban tsarin za a iya tantance shi kai tsaye. Adadin da ke bayyana yanayin babban tsarin sune zafin jiki (T), matsin lamba (p), girma (V), da taro (m) ko adadin moles (n). Zafi da aiki suna da hannu ne kawai a cikin tsarin canja wurin makamashi tsakanin tsarin da kewayensa; ba adadi ne ke bayyana yanayin tsarin ba.
Sanya hannu kan ƙa'idodi don Zafi (Q) da Aiki (W)
Dokokin alamun zafi da aiki sun yi daidai da Dokar Farko ta Thermodynamics. Zafi (Q) a cikin lissafin da ke sama yana wakiltar zafi da aka ƙara wa tsarin (Q yana da kyau), yayin da Aiki (W) a cikin lissafin da ke sama yana wakiltar aikin da tsarin ya yi (W yana da kyau). Idan zafi ya bar tsarin, to Q yana da kyau. Akasin haka, idan an yi aiki akan tsarin, to W yana da kyau.
Misali tambaya ta 1:
Idan aka ƙara Joules 2000 na zafi a cikin tsarin, yayin da tsarin ke yin Joules 1000 na aiki, menene canjin makamashin ciki na tsarin?
Tattaunawa
Tsarin yana karɓar ƙarin zafi (makamashi) na Joules 2000. Tsarin kuma yana yin aiki (sakin makamashi) na Joules 1000. Saboda haka, canjin kuzarin tsarin = Joules 1000.
Misali tambaya ta 2:
Idan Joules 2000 na zafi ya bar tsarin kuma tsarin yana yin Joules 1000 na aiki, menene canjin makamashin ciki na tsarin?
Tattaunawa
Idan zafi ya fita daga tsarin, yana nufin cewa Q yana da ƙimar mara kyau.
Jul 2000 na zafi yana barin tsarin (tsarin yana fitar da makamashi). Jul 1000 na aiki kuma ana yin sa (tsarin yana fitar da makamashi). Don haka, kuzarin da ke cikin tsarin yana raguwa da 3000 J.
Misali tambaya ta 3:
Idan aka ƙara Joules 2000 na zafi a cikin tsarin kuma aka yi Joules 1000 na aiki akan tsarin, menene canjin makamashin ciki na tsarin?
Tattaunawa
Idan an yi aiki akan tsarin, to W yana da komfuta.
Tsarin yana karɓar ƙarin zafi (tsarin yana karɓar makamashi) na Joules 2000 kuma ana yin aiki akan tsarin (tsarin yana karɓar makamashi) na Joules 1000. Don haka, kuzarin da ke cikin tsarin yana ƙaruwa da Joules 3000.
Da farko , yawancin tsarin da muke nazari a ka'ida a cikin wannan batu iskar gas ce. Muna amfani da iskar gas saboda halayensu na macroscopic (zafin jiki, matsin lamba, da girma) sun fi sauƙin tantancewa. Wajen nazarin iskar gas, har yanzu muna ɗaukar su a matsayin iskar gas mafi kyau. Wannan kawai don sauƙaƙe nazarin ne. Ba ma amfani da iskar gas ta gaske saboda, a lokacin matsin lamba mai yawa, iskar gas ta gaske yawanci tana yin abubuwa marasa kyau.
Na biyu , idan tsarin da muke nazari a kai gas ne mai kyau, to za a iya ƙididdige makamashin ciki ta amfani da lissafin da ke nuna alaƙar da ke tsakanin makamashin ciki na iskar gas mai kyau da zafin iskar gas mai kyau: U = 3/2 nRT (ƙididdigar makamashin ciki don iskar gas mai kyau ta monatomic).
Aikin da tsarin ya yi yayin canjin girma
Kafin mu ci gaba, bari mu fara la'akari da aikin da tsarin ke yi a kewayensa. Don ƙididdige adadin aikin (W) da tsarin ya yi, yi la'akari da iskar gas mai kyau a cikin akwati da piston ya rufe. Ana iya motsa piston ɗin sama da ƙasa. An sauƙaƙe wannan adadi zuwa girma biyu. Yi la'akari da shi mai girma uku. Ƙara = tsayi x faɗi x tsayi.
Ana wakiltar iskar gas mai kyau ta hanyar wuraren da ke cikin akwati. Tushen akwatin yana hulɗa da wani abu mai zafi sosai (kamar ruwa a cikin kasko da aka dumama a kan harshen wuta). Ba a haɗa abin da ke da zafi sosai a cikin hoton ba, kawai ka yi tunanin hakan a zuciyarka 😉 Iskar gas mai kyau a cikin akwatin ita ce tsarin, yayin da sauran abubuwa a wajen akwatin, gami da abin da ke da zafi sosai da ke hulɗa da tushen akwatin, su ne muhalli. Saboda zafin jiki na yanayi ya fi zafin tsarin, zafi yana gudana ta halitta daga muhalli zuwa tsarin. Ƙarin kuzari daga muhalli yana sa kuzarin ciki na tsarin (iskar gas mai kyau) ya ƙaru. Ƙarfin ciki na iskar gas mai kyau yana daidai da zafin jiki kai tsaye (U = 3/2 nRT), don haka lokacin da kuzarin ciki na iskar gas mai kyau ya ƙaru, zafin iskar gas mai kyau shi ma yana ƙaruwa. Ƙaruwar zafin jiki na iskar gas mai kyau yana sa iskar gas mai kyau ta faɗaɗa kuma ta tura piston a nisa s. Lokacin tura piston a nisa s, tsarin (iskar gas mai kyau) yana aiki akan muhalli (iska ta waje).
Da farko, matsin lambar tsarin yana da yawa (P1) kuma ƙarfin tsarin yana da ƙasa (V1). Matsi yana da daidaiton juzu'i. Bayan zafi ya kwarara daga kewaye zuwa tsarin kuma tsarin ya yi aiki akan kewaye, ƙarar tsarin yana ƙaruwa (V2) kuma matsin lambar tsarin yana raguwa (P2).
Adadin aikin da tsarin ya yi a cikin tsarin da ke sama shine:
Aiki (W) = Ƙarfin turawa (F) x ƙaura (s). Tunda ƙarfin turawa (F) = matsi (P) x yankin saman (A) na piston, ana iya rubuta lissafin aiki kamar haka:
W = Fs ‐‐‐‐ F = PA
W = PAs - - - - - kamar yadda = V
W = PV
Yana da mahimmanci a lura cewa aikin da tsarin ya yi yana faruwa ne yayin canjin girma. Saboda haka, jimlar aikin da tsarin ya yi za a iya samu ta hanyar ninka canjin matsin lamba da canjin girma. A lissafi:
W = (matsin ƙarshe - matsin lamba na farko) (ƙarfin ƙarshe - ƙarar farko)
W = (P2 - P1 ) ( V2 - V1 )
Da farko , ana iya tantance canjin girman tsarin cikin sauƙi. Ana iya tantance girman farko da na ƙarshe na tsarin ta hanyar ƙididdige girman akwatin. Saboda haka, don ƙididdige adadin aikin (W) da tsarin ya yi, muna buƙatar sanin yadda matsin lamba ke canzawa yayin aikin.
Idan matsin lamba (p) na wani tsari ya canza ba bisa ka'ida ba yayin da girman (V) ke canzawa, to ana iya ƙididdige adadin aikin da tsarin ya yi ta amfani da kalkuleta. Idan ba ku saba da kalkuleta ba, akwai wasu hanyoyin da za ku iya amfani da su. Da farko, bari mu zana jadawali wanda ke nuna alaƙar da ke tsakanin matsin lamba da girma. Adadin aikin da tsarin ya yi = yankin da aka yi inuwa a ƙarƙashin lanƙwasa p-V.
Jadawalin matsin lamba da girma don canje-canjen matsin lamba waɗanda ke faruwa ba bisa ƙa'ida ba.
Da farko, matsin lamba na tsarin = p 1 (matsin lamba mai yawa) da kuma girman tsarin = V 1 (ƙaramin girma). Bayan tsarin ya yi aiki a kan muhalli, matsin lamba na tsarin yana canzawa zuwa p 2 (ƙaramin matsin lamba) kuma girman tsarin yana canzawa zuwa V 2 (ƙaramin girma). Adadin aikin (W) da tsarin ya yi = yankin da aka yi inuwa. Siffar lanƙwasa tana lanƙwasa saboda matsin lamba na tsarin (iskar gas mai kyau) yana canzawa ba tare da tsari ba yayin aikin.
Idan matsin lamba (p) na wani tsari ya kasance daidai yayin da girma (V) ke canzawa, to ana iya ƙididdige adadin aikin da tsarin ya yi cikin sauƙi. Ana iya ƙididdige adadin aikin da tsarin ya yi ta amfani da lissafi ko kuma ana iya samunsa daga yankin da aka yi inuwa a ƙarƙashin lanƙwasa P-V. A wannan yanayin, ana iya gyara lissafin aikin da ke sama kamar haka:
W = (P2 - P1 ) ( V2 - V1 )
Tunda matsin lamba (p) koyaushe yana dawwama, to P 2 = P 1 = P
W = P ( V2 - V1 )
Jadawalin matsin lamba da girma don tsari inda matsin lamba koyaushe yake canzawa, watau baya canzawa:
Da farko girman tsarin = V1 (ƙaramin girma). Bayan tsarin ya yi aiki a kan muhalli, girman tsarin zai canza zuwa V2 (babban girma). Matsi na tsarin koyaushe yana da daidaito, ma'ana ba ya canzawa. Adadin aikin (W) da tsarin yayi = yankin da aka yi inuwa.
Na biyu, tsarin yana aiki akan muhalli idan girman tsarin ya ƙaru. Akasin haka, muhalli yana aiki akan tsarin idan girman tsarin ya ragu. Idan girman tsarin bai canza ba yayin aikin, tsarin ba zai iya yin aiki akan muhalli ba, kuma muhallin ba zai iya yin aiki akan tsarin ba. A wannan yanayin, aiki (W) = 0.
