Imibuzo eyisibonelo namafomula wamandla kagesi namandla
Amandla kanye namandla kagesi
1. Izinga likagesi nge-kWh yi-Rp. 400. Endlini, i-TV engu-100 Watt isebenza amahora ama-4 ngosuku, kanti izibani ezimbili zama-Watts angu-20 ngalinye zisetshenziswa amahora ayi-10 ngosuku. Izindleko zokusebenzisa ugesi ngenyanga (izinsuku ezingu-30)….
A. Rp. 4.800,-
B. Rp. 9.600,-
C. Rp. 19.200,-
D. Rp. 21.120,-
Ingxoxo
Kuyaziwa ukuthi:
Intengo kagesi ingu-Rp. 400/kWh
Amandla e-TV = 1 x 100 Watt = 100 Watt kanye nesikhathi sokusetshenziswa kwe-TV = amahora ama-4 x 30 = amahora ayi-120
Amandla esibani = 2 x 20 Watt = 40 Watt kanye nesikhathi sokusetshenziswa kwesibani = amahora ayi-10 x 30 = amahora angama-300
Kubuziwe: Izindleko zokusetshenziswa kukagesi ngenyanga
Impendulo:
Amandla kagesi = amandla kagesi x isikhathi sokusetshenziswa
Amandla kagesi e-TV = 100 Watt x 120 hours = 12.000 Watt hours
Amandla esibani = 40 Watt x amahora angu-300 = amahora angu-12.000 Watt
Amandla aphelele = amahora angu-12.000 Watt + amahora angu-12.000 Watt = amahora angu-24.000 Watt = amahora angu-24 Watt = amahora angu-24 Watt = amahora angu-24 Watt = amahora angu-24 Watt = 24 kWh
Izindleko zokusetshenziswa kukagesi ngenyanga = (24 kWh)(Rp. 400/kWh) = (24)(Rp. 400) = Rp. 9.600,-
Impendulo efanele ingu-B.
2. Izibani ezimbili, ngasinye esinelebula engu-24 Watt / 12 Volt, zixhunywe ngokufana, bese zixhunywe ngokulandelana nge-resistor engu-2 Ohm. Le sekethe ixhunywe emthonjeni we-voltage ukuze zombili izibani zikhanyise ngo-25% kuphela wokukhanya kwazo okuphezulu. Uma isibani esisodwa siphuka ngokuzumayo, esinye isibani sizokhanya ngamandla….
A. Ama-Watts angu-12
B. 7,5 Watts
C. 6 Watts
Ama-watt angu-D. 3
Ingxoxo
Ifomula yamandla:
P = VI
I = i-PV
noma
P = VI —–> I = V / R
P = V (V / R)
P=V2 /R
R = V2 /P
noma
P = VI —–> V = IR
P = (IR) I
P = ngi2 R
I2 = P / R
Incazelo: P = amandla kagesi, V = i-voltage kagesi, I = ugesi wamanje, R = ukumelana nesibani
Bala ukumelana kwesekethe:
Izibani ezimbili ngayinye ziphawulwe ngokuthi yi-24 Watt / 12 Volt, okusho ukuthi isibani ngasinye sizokhanya ngamandla aphezulu angama-24 Watts uma sixhunywe ku-voltage engama-12 Volts.
Ukumelana kwesibani ngasinye kubalwa kusetshenziswa ifomula yamandla:
R = V2 / P = 122 / 24 = 144 / 24 = 6 Ohms
Izibani ezimbili zixhunywe ngokulingana ngakho ukumelana okulinganayo yilokhu:
1 / R12 = 1/R1 +1/R2 = 1/6 + 1/6 = 2/6
R12 = 6/2 = 3 Ohms
Izibani ezimbili zixhunywe ngokulandelana nge-resistor engu-2 Ohm ngakho ukumelana okulinganayo yilokhu:
R = 3 Ohm + 2 Ohm = 5 Ohm
Ngakho ukumelana kwesekethe = R = 5 Ohm.
Bala ugesi ogeleza kusekethe:
Uma izibani zombili zivuliwe ngezinga lokukhanya elingu-25% khona-ke zombili izibani zivuliwe ngamandla angu-25/100 x 24 Watts = 1/4 x 24 = 24/4 = 6 Watts.
Ugesi ogeleza esibanini ubalwa kusetshenziswa ifomula yamandla:
I2 = P / R = 6 Watts / 6 Ohms = 1 Ampere
Ugesi ogeleza ngesibani ngasinye uyi-1 Ampere. Izibani ezimbili zixhunywe ngasikhathi sinye, ngakho-ke ngokomthetho wokuqala kaKirchhoff, ugesi ophelele ogeleza kuzo zombili izibani uyi-2 Ampere. Izibani ezimbili zixhunywe ngokulandelana nge-resistor engu-2 Ohm, ngakho-ke ugesi ogeleza ngesivikelo esingu-2 Ohm nawo uyi-2 Ampere.
Ngakho-ke ugesi ogeleza kusekethe = I = 2 Amperes.
Bala i-voltage yomthombo we-emf:
I-voltage kagesi yile:
V = IR = (2 Ampere)(5 Ohm) = 10 Volts
Lena yi-voltage yomthombo we-EMF onani layo alishintshi ngaphambi kokuba elinye lamalambu liphuke noma ngemva kokuba elinye lamalambu liphuke.
Bala ukumelana kwesekethe ngemva kokuphuka kwesinye sezibani:
Uma esinye sezibani siphuka, esinye isibani esisavuliwe sixhunywe ngokulandelana nge-resistor engu-2 Ohm. Ngakho-ke, ukumelana kwesekethe kushintshela ku:
R = 6 Ohm + 2 Ohm = 8 Ohm
Bala ugesi ogeleza kusekethe ngemva kokuphuka kwesinye sezibani:
Ugesi ogeleza kusekethe uthi:
I = V / R = 10 Volts / 8 Ohms = 1,25 Amps
Isibani kanye ne-resistor kuxhunywe ngokulandelana ukuze ugesi ogeleza kwisekethe = ugesi ogeleza esibanini = ugesi ogeleza kwi-resistor.
Bala amandla esibani:
Ngemva kokuba esinye sezibani siphumile, ezinye izibani zikhanya ngamandla ka:
P = VI = (10 Volt)(1,25 Ampere) = 12,5 Watt
Ukunyakaza kwama-electron
3. Isisindo se-electron saziwa ngokuthi singu-9,1 x 10-31 kg kanye neshaja ye-electron 1,6 x 10-19 C. Umehluko ongaba khona odingekayo ukuze kusheshiswe i-electron kusukela esilinganisweni esingu-1 x 105 m/s iba ngu-3 x 105 i-m/s i….
A. 28,4375 mV
B. 56,875 mV
C. 113,75 mV
D. 227,5 mV
Ingxoxo
Kuyaziwa ukuthi:
Isisindo se-electron (m) = 9,1 x 10-31 kg
Ishaja ye-electron (q) = 1,6 x 10-19 C
Ijubane lokuqala (v)o) = 1 x 105 m/s —> vo2 = 1 x1010 m2/s2
Ijubane lokugcina (v)t) = 3 x 105 m/s —> vt2 = 9 x 1010 m2/s2
Kubuziwe: Umehluko ongase ube khona (V) odingekayo ukuze kusheshiswe i-electron
Impendulo:
Ushintsho emandleni kagesi = q V = (1,6 x 10-19 C) V
Ushintsho kumandla e-kinetic = EKt – EKo = 1/2 m (vt2 - vo2) = 1/2 (9,1 x 10-31 kg)(9 x 1010 m2/s2 - 1 x 1010 m2/s2) = (4,55 x 10-31 kg)(8 x 1010 m2/s2) = 36,4 x 10-21 kg m2/s2
Amandla angunaphakade ukuze amandla kagesi ashintshe abe amandla e-kinetic:
I-EPL ilahlekile = i-EK ivele
(1,6x10-19) V = 36,4 x 10-21
V = 36,4 x 10-21 1,6x10-19
V = 22,75 x 10-2 I-Volt
V = 227,5 x 10-3 I-Volt
V = 227,5 milliVolts
Impendulo efanele ngu-D.
4. Imibuzo ye-National Science Olympiad ka-2011 yezikole zamabanga aphezulu zase-Junior ezingeni le-Regency/Dolobha No. 56
Elabhorethri, umshayo wama-electron udutshulwa uye enyakatho. Ukusuka phezulu, kuqashelwa ukuthi umshayo ugoba uye kwesobunxele. Bese, umshayo wama-electron udutshulwa uye eningizimu. Ukusuka phezulu, kuqashelwa ukuthi umshayo ugoba uye kwesobunxele. Lokhu kusho ukuthi kukhona…
A. insimu kagesi ekhomba entshonalanga
B. insimu kagesi ekhomba empumalanga
C. insimu yamagnetic eqondiswe phezulu
D. insimu yamagnetic eqondiswe phansi
Ingxoxo
Ama-electron ashajwa ngogesi futhi angashukunyiswa amandla kagesi noma amagnetic uma esensimini kagesi noma yamagnetic. Umehluko ukuthi amandla kagesi angashukumisa ama-electron kokubili lapho ephumulile nalapho ehamba, kuyilapho amandla amagnetic engashukumisa ama-electron kuphela uma ehamba.
Omunye umehluko ukuthi amandla kagesi asendaweni efanayo nensimu kagesi, kuyilapho amandla kazibuthe eqondene nensimu kazibuthe. Ngakho-ke, uma i-electron ishukunyiswa amandla kagesi, isiqondiso sokunyakaza kwayo sifana nesiqondiso sensimu kagesi. Ngokuphambene nalokho, uma i-electron ishukunyiswa amandla kazibuthe, isiqondiso sokunyakaza kwayo sifana nesiqondiso samandla kazibuthe, esiqondene nesiqondiso sensimu kazibuthe.
Ngokusekelwe embuzweni ongenhla, kubonakala sengathi uma i-electron idutshulwa enyakatho, iphendukela ngakwesobunxele (ngasentshonalanga), futhi uma idutshulwa ngaseningizimu, iphendukela ngakwesobunxele (ngasempumalanga). Uma i-electron iphendukela ngamandla kagesi, khona-ke isiqondiso samandla kagesi, esifana nesiqondiso sensimu kagesi, sihlala sishintsha. Isiqondiso sensimu kagesi kufanele sihlale singaguquguquki. Ngakho-ke, i-electron ayiphendukeli ngamandla kagesi.
Kungaphethwa ngokuthi amandla kazibuthe aphendukezela ama-electron. Ukuze uthole ukuthi amandla kazibuthe aqondiswa kanjani (indlela ama-electron aphendukezela ngayo), isiqondiso sensimu kazibuthe, kanye nesiqondiso ama-electron aqhutshwa ngaso, sebenzisa umthetho wesandla sokudla.
Sebenzisa umthetho wesandla sokudla njengoba kuchaziwe ngezansi. Yelula isandla sakho sokudla, qondisa isithupha sakho bese uvala eminye iminwe yakho emine. Beka isithupha sakho ukuze sibheke enyakatho (isiqondiso sokunyakaza kwama-electron) bese iminwe yakho emine ibheke entshonalanga (isiqondiso samandla kazibuthe = isiqondiso sokuguquka kwama-electron), bese ingemuva lesandla sakho sokudla lizokhomba phansi (isiqondiso sensimu kazibuthe). Ngokuphambene nalokho, beka isithupha sakho ukuze sibheke eningizimu (isiqondiso sokunyakaza kwama-electron) bese iminwe yakho emine ikhomba empumalanga (isiqondiso samandla kazibuthe = isiqondiso sokuguquka kwama-electron), bese ingemuva lesandla sakho sokudla lizokhomba phansi (isiqondiso sensimu kazibuthe). Kungaphethwa ngokuthi i-electron isensimini kazibuthe eqondiswe phansi.
Impendulo efanele ngu-D.
Umthombo wombuzo:
Imibuzo ye-OSN yeFiziksi yeSikole Samabanga Aphezulu
