Zitsanzo za Mafunso Okhudza Kukambirana za Microwave
Ma microwave ndi gawo la ma electromagnetic spectrum okhala ndi mafunde kuyambira 1 mm mpaka 1 m. Mafunde awa amagwiritsidwa ntchito nthawi zambiri muukadaulo wamakono, monga kulumikizana popanda zingwe, radar, zakuthambo, ndi zida zapakhomo monga ma microwave ovens. Popeza kufunika kwa ma microwave, ndikofunikira kuti ophunzira, makamaka omwe akuphunzira sayansi ya fizikisi kapena uinjiniya, amvetsetse zoyambira za ma microwave, kuphatikizapo momwe angathetsere mavuto okhudzana nawo. Nkhaniyi ikambirana zitsanzo zingapo za mavuto ndikukambirana za ma microwave.
Funso 1: Kutalika kwa Mafunde ndi Kuchuluka kwa Mafunde
Funso:
Popeza kuti microwave ili ndi ma frequency a 10 GHz, werengani kutalika kwa mafunde a microwave. (Gwiritsani ntchito liwiro la kuwala c = 3 x 10^8 m/s)
Kukambirana:
Choyamba, timakumbukira ubale womwe ulipo pakati pa kutalika kwa mafunde (λ), mafupipafupi (f), ndi liwiro la kuwala (c):
\[ c = \lambda \cdot f \]
Tikhoza kapena kubwereza fomula iyi kuti tipeze wavelength (λ):
\[ \lambda = \frac{c}{f} \]
Popeza ma frequency (f) = 10 GHz = 10 x 10^9 Hz, ndi liwiro la kuwala (c) = 3 x 10^8 m/s, timalumikiza mfundo ziwirizi mu fomula iyi:
\[ \lambda = \frac{3 \times 10^8 \, \text{m/s}}{10 \times 10^9 \, \text{Hz}} \]
\[ \lambda = 0.03 \, \text{m} \]
Kotero, kutalika kwa mafunde a microwave ndi 0,03 metres kapena 3 cm.
Funso 2: Mphamvu Yotumizira ndi Kutalikirana
Funso:
Chotumizira cha microwave chimatulutsa mphamvu ya 50 W. Werengani mphamvu ya microwave pamtunda wa mamita awiri kuchokera ku gwero la chotumizira, poganiza kuti kufalikira kwa isotropic kukuchitika.
Kukambirana:
Kuti tiwerenge mphamvu, timagwiritsa ntchito equation ya mphamvu pa gawo lililonse:
\[ I = \frac{P}{A} \]
P ndi mphamvu (50 W) ndipo A ndi malo a pamwamba pa bolodi lokhala ndi utali wa mamita awiri:
\[ A = 4 \pi r^2 \]
Lowetsani mtengo r = mamita awiri mu fomula ya dera:
\[ A = 4 \pi (2 \, \text{m})^2 \]
\[ A = 16 \pi \, \text{m}^2 \]
Kenako werengani mphamvu:
\[ I = \frac{50 \, \text{W}}{16 \pi \, \text{m}^2} \]
Kuwerengera manambala:
\[ I \pafupifupi \frac{50}{50.265} \]
\[ I \pafupifupi 0.995 \, \malemba{W/m}^2 \]
Choncho, mphamvu ya microwave pamtunda wa mamita awiri kuchokera ku gwero la transmitter ndi pafupifupi 0.995 W/m².
Funso 3: Doppler Effect mu Ma Microwave
Funso:
Galimoto yoyenda pa liwiro la 108 km/h (30 m/s) ikuyandikira ma microwave otumiza radar pa liwiro la 5 GHz. Werengani kuchuluka komwe radar imalandira ngati liwiro la microwave ndi liwiro la kuwala.
Kukambirana:
Gwiritsani ntchito Doppler effect pa ma frequency olandiridwa (f'):
\[ f' = f \left(\frac{c + v}{c}\right) \]
Kumene:
– f' = pafupipafupi yolandiridwa
– f = ma frequency ochokera = 5 GHz = 5 x 10^9 Hz
– c = liwiro la kuwala = 3 x 10^8 m/s
– v = liwiro la galimoto = 30 m/s
Sinthani mfundozo mu fomula iyi:
\[ f' = 5 \nthawi 10^9 \kumanzere(\frac{3 \nthawi 10^8 + 30}{3 \nthawi 10^8}\kumanja) \]
\[ f' \pafupifupi 5 \nthawi 10^9 \kumanzere(1 + \frac{30}{3 \nthawi 10^8}\kumanja) \]
\[ f' \pafupifupi 5 \nthawi 10^9 \kumanzere(1 + 1 \nthawi 10^{-7}\kumanja) \]
\[ f' \pafupifupi 5 \nthawi 10^9 \nthawi 1.0000001 \]
\[ f' \pafupifupi 5.0000005 \nthawi 10^9 \]
\[ f' \pafupifupi 5.0000005 \, \malemba{GHz} \]
Kotero, ma frequency omwe amalandiridwa ndi radar ndi pafupifupi 5.0000005 GHz.
Funso 4: Kutengera Mphamvu ndi Zipangizo
Funso:
Chipangizo china chimayamwa mphamvu ya maikulowevu ya 2 W pamene mphamvu ya mafunde ochitika ndi 10 W/m². Werengani malo a pamwamba pa chipangizocho.
Kukambirana:
Gwiritsani ntchito ubale pakati pa mphamvu yoyamwa ndi malo a pamwamba ndi mphamvu yake:
\[ P = I \cdot A \]
M'malo mwa mfundo zodziwika bwino:
\[ 2 \, \malemba{W} = 10 \, \malemba{W/m}^2 \cdot A \]
Kuthetsa vuto la A:
\[ A = \frac{2 \, \text{W}}{10 \, \text{W/m}^2} \]
\[ A = 0.2 \, \malemba{m}^2 \]
Choncho, pamwamba pa zinthuzo ndi 0,2 m².
Funso 5: Kusinkhasinkha ndi Kusokoneza
Funso:
Ma antenna awiri a microwave amatulutsa mafunde a kutalika kwa 6 cm mbali imodzi. Ngati mtunda pakati pa ma antenna ndi 12 cm, ndi nthawi iti yomwe kusokoneza kwa zinthu kumachitika koyamba?
Kukambirana:
Kusokoneza komanga kumachitika pamene kusiyana kwa njira pakati pa magwero awiriwa ndi k = ±nλ (n ndi nambala yopanda zero kuphatikiza 0). Kwa nthawi yoyamba kusokoneza komanga (n=1):
\[ d = n \lambda/2 \]
Popeza mtunda wa antenna ndi 12 cm ndipo kutalika kwa mtunda ndi 6 cm, kusiyana kwa njira yolumikizira koyamba kumachitika pa:
\[ d = n (\lambda/2) \]
Kotero:
\[ 12 = 1 \nthawi (6/2) \]
Kotero mtunda womwe uli pano ndi:
\[ 12 = 1 \nthawi 3 \]
Chifukwa chakuti equation iyi ikugwirizana ndi kupangika kwa mapatani osokoneza pa zomwe zili wamba, ndiye kuchokera ku lingaliro lomwe timapanga pamzere wapakati wa mtunda kuchokera ku gwero kapena njira kutengera malo osakhala a njanji, kutanthauza malo okhazikika a mzere wotsatira omwe sakugwirizana ndi mawonekedwe okhazikika omwe akuyembekezeka.
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Izi ndi zitsanzo za mavuto a microwave ndi momwe mungawathetsere. Mwa kumvetsetsa ndi kuzolowera kuthetsa mavuto ngati awa, tikukhulupirira kuti zidzakhala zosavuta kuti mumvetse ndikugwiritsa ntchito mfundo za microwave m'magawo osiyanasiyana a sayansi ndi ukadaulo.
