2 Tusaalooyin su'aalo ah oo ku saabsan qalabka indhaha ee indhaha
1. Qof leh indhaha caadiga ah Inaad aragto shay meel fog, halkaas oo barta fog ee isha caadiga ah ay tahay mid aan dhammaad lahayn. Dhererka diiradda ee muraayadda indhaha ayaa la mid ah masaafada u dhaxaysa cornea iyo retina, oo ah 2,5 cm, waxay go'aamisaa (a) masaafada sawirka, (b) awoodda muraayadda.
Dood
Nidaamka muraayadda indhaha ee cornea-lens-ka ayaa u shaqeeya inuu dib u jaro oo diiradda saaro fallaaraha iftiinka ee soo galaya isha. Haddii kaliya cornea-ga la xuso, u qaado in cornea-ga oo keliya uu dib u jaro fallaaraha iftiinka. Cornea-gu wuxuu u shaqeeyaa sida muraayadda convex ama muraayadda convex. muraayad isku soo ururaysa kaas oo diiradda saaraya iftiinka hal dhibic.
Waa la garanayaa :
Dhererka isha (f) = masaafada u dhaxaysa isha iyo isha = +2,5 cm (togan sababtoo ah waa muraayad qaloocan).
Masaafada walxaha (yada) = xad la'aan
La weydiiyay : masaafada sawirka (yada)
Jawab :
(a) Masaafada hooska
1/f = 1/s + 1/s'
Sharaxaad: f = dhererka diiradda, s = masaafada shayga, s' = masaafada sawirka
1/s' = 1/f – 1/s = 1 / 2,5 – 1 / ~ = 1 / 2,5 – 0
1/s' = 1 / 2,5
s' = 2,5 cm = 0,025 mitir
Haddii masaafada (yada) shayga ay tahay mid aan dhammaad lahayn markaa masaafada (yada) sawirka = dhererka diiradda (f).
(b) awoodda korontada ama muraayadda (P)
P = 1/f = 1/0,025 mitir = 40 Diopters
2. Qof indho caadi ah leh wuxuu shay ku arkayaa meel u dhow, halkaas oo meesha ugu dhow ee isha caadiga ah ay tahay 25 cm. Masaafada sawirku waxay la mid tahay masaafada u dhaxaysa cornea iyo retina, oo ah 2,5 cm. Go'aami (a) dhererka diiradda, (b) awoodda muraayadda.
Dood
Waa la garanayaa :
Masaafada shayga (yada) = 25 cm
Masaafada sawirka (yada) = 2,5 cm (sawirku waa inuu ku yaal isha si shayga si cad loogu arko. Isbarbardhig doodda su'aasha lambarka 1)
Jawab :
(a) dhererka diiradda (f)
1/f = 1/s + 1/s'
1/f = 1/25 + 1/2,5 = 1/25 + 10/25 = 11/25
f = 2,27 cm = 0,0227 mitir
Dhererka diiradda waa mid togan sababtoo ah waa muraayad isku laaban ama isku soo urursan. Masaafada sawirka ayaa ka weyn halka dhererka diiradda uu ka yar yahay. Farqiga u dhexeeya masaafada sawirka iyo dhererka diiradda = masaafada u dhaxaysa barta diiradda iyo barta sawirka = 2,5 cm – 2,27 cm = 0,23 cm.
(b) Awoodda muraayadda (P)
P = 1/f = 1/0,0227 = 44 Diopters
Gunaanad:
Iyada oo lagu saleynayo doodda su'aalaha 1aad iyo 2aad, waxaa lagu soo gabagabeyn karaa in:
– Farqiga dhererka diiradda marka isha ay ku aragto shay aan dhammaad lahayn (meel fog) iyo masaafada 25 cm (meel u dhow) waa 2,5 cm – 2,27 cm = 0,23 cm = 0,0023 mitir.
– Farqiga u dhexeeya xoogga muraayadda, oo sidoo kale loo yaqaan awoodda muraayadda indhaha marka la daawanayo shay masaafad aan dhammaad lahayn (meel fog) iyo masaafad 25 cm ah (meel u dhow) waa 44 D – 40 D = 4 Diopters.
Su'aalo ku saabsan Qalabka Indhaha
1. Qof indho caadi ah leh wuxuu arkayaa shay meel 50 mitir u jirta isha. Haddii masaafada u dhaxaysa cornea iyo retina ay tahay 2,5 cm, go'aami (a) dhererka diiradda ee nidaamka muraayadda indhaha, (b) awoodda nidaamka muraayadda indhaha.
Furaha jawaabta:
a = 2,499 cm
b = 40,016 diopters
2. Qof indho caadi ah leh ayaa indhahiisa ka wareejiya shay 100 mitir u jira una wareejiya shay 1 mitir u jira. Masaafada u dhaxaysa cornea iyo retina waa 2,5 cm. Xisaabi (a) isbeddelka dhererka diiradda ee nidaamka muraayadda indhaha, (b) isbeddelka awoodda nidaamka muraayadda indhaha.
Furaha jawaabta:
a = 0,06 cm
b = 1 diopters
