Aragti dhow iyo aragti fog waxaa lagu sixi karaa muraayadaha indhaha iyo muraayadaha indhaha . Muraayadaha indhaha waxaa lagu dhejiyaa muraayadaha indhaha, halka muraayadaha indhaha lagu dhejiyo ay ku xiran yihiin isha. Muraayadaha indhaha waxay ku yaalliin meel u jirta isha, halka muraayadaha indhaha lagu dhejiyo ay ku xiran yihiin isha, sidaa darteed masaafada u dhaxaysa muraayadda indhaha iyo isha waa mid aan la taaban karin.
Maqaalkani wuxuu sharxayaa tusaalooyin ku saabsan dhibaatooyinka ay la kulmaan dadka aragtida fog iyo kuwa aragtida fog, noocyada muraayadaha loo isticmaalo sixitaanka aragtida, dhererkooda diiradda, iyo awooddooda. Maqaalkani wuxuu diiradda saarayaa isticmaalka muraayadaha si loo saxo indhaha aragtida fog iyo kuwa aragtida fog.
Muraayadaha Aragga Dhow iyo Muraayadaha Concave
Meel fog isha aragga fog ama myopia waa 102 cm. Si isha aragga dhow ay si cad ugu aragto walxaha aan dhammaadka lahayn, go'aami (a) nooca muraayadda la isticmaalay, (b) dhererka diiradda muraayadda, (c) xoogga ama awoodda muraayadda.
Muraayadaha muraayadaha ayaa guud ahaan 2 cm u jira indhaha.
Dood
(A) Nooca muraayadda la isticmaalay
Mawduuca ku saabsan aragti fog Waxaa la sharraxay in muraayadaha loo isticmaalo in lagu caadiyeeyo indhaha aan aragga lahayn ay yihiin muraayadaha indhaha ee wareegsan ama muraayadaha indhaha ee kala duwan ama muraayadaha taban.
(B) Dhererka diiradda muraayadda
Si shay ay isha indho la'aantu ku aragto iyada oo adeegsanaysa muraayad muraayad ah uu u ahaado mid aad u fog, muraayaddu waa inay sawir ka sameysaa masaafo dhan 102 cm oo ku taal indhaha hortiisa, taas oo ah meesha ugu fog ee isha indho la'aanta ah. Muraayadda muraayaddu waxay u jirtaa isha 2 cm sidaas darteed sawirku waa 100 cm oo ku taal muraayadda horteeda. Sawirku wuxuu ku yaal muraayadda horteeda, sidaas darteed sawirku waa mid casri ah oo toosan (isbarbardhig sharraxaadda mawduuca). sawirka muraayadda qaloocan)
Waa la garanayaa :
Masaafada walxaha (yada) = xad la'aan
Masaafada sawirka (yada) = -100 cm (taban sababtoo ah sawirku waa mid casri ah)
La weydiiyay Dhererka (f)
Jawab :
1/f = 1/s + 1/s'
1/f = 1/~ + (- 1/100)
1/f = 0 – 1/100
1/f = – 1/100
f = – 100/1 cm = -100 cm = -1 mitir.
Dhererka diiradda taban macnaheedu waa in muraayadda la isticmaalay ay tahay muraayad qaloocan ama muraayad kala duwan.
(C) Awoodda muraayadda
P = 1/f = 1/-1 m = -1 Diopter
Xoogga ama awoodda muraayadda waa -1 D. Calaamadda taban waxay ka dhigan tahay in muraayadda la isticmaalay ay tahay muraayad qaloocan ama muraayad kala duwan.
Muraayadaha Aragga Dhow iyo Muraayadaha Qunyar-socodka ah
Barta u dhow isha qofka aan arag wax dhow ah waa 102 cm. Si qofku u awoodo inuu wax ku akhriyo masaafad dhan 25 cm horteeda isha, go'aami (a) nooca muraayadda la isticmaalay, (b) dhererka diiradda muraayadda, (c) awoodda muraayadda.
Muraayadaha muraayadaha ayaa guud ahaan 2 cm u jira indhaha.
Dood
(A) Nooca muraayadda la isticmaalay
Mawduuca ku saabsan aragti fog Waxaa la sharraxay in muraayadaha loo isticmaalo in lagu caadiyeeyo indhaha aan aragga lahayn ay yihiin muraayadaha wareegsan ama muraayadaha isku dhafan ama muraayadaha togan.
(B) Dhererka diiradda muraayadda
Si shay loo arko inuu 25 cm u jiro indhaha hortiisa, muraayaddu waa inay sawir ka sameysaa masaafo dhan 102 cm oo ku taal indhaha hortiisa, taasoo ah meesha ugu dhow ee isha aan la arki karin. Muraayadda muraayadda indhaha waxay u jirtaa isha 2 cm, sidaa darteed sawirku waa inuu ahaadaa 100 cm oo ku taal muraayadda horteeda, shayguna waa inuu ahaadaa 23 cm oo ku taal muraayadda horteeda. Sawirku wuxuu ku yaal muraayadda horteeda, sidaas darteed sawirku waa inuu ahaadaa mid toosan oo casri ah (isbarbardhig sharraxaadda mawduuca). sawirka muraayadda qaloocan)
Waa la garanayaa :
Masaafada shayga (yada) = 23 cm
Masaafada sawirka (yada) = -100 cm (taban sababtoo ah waa mid casri ah)
La weydiiyay Dhererka diiradda (f)
Jawab :
1/f = 1/s + 1/s'
1/f = 1/23 + 1/-100
1/f = 1/23 – 1/100
1/f = 100/2300 – 23/2300
1/f = 77/2300
f = 2300/77 = 30 cm = 0,3 mitir
Dhererka diiradda togan macnaheedu waa in muraayadda la isticmaalay ay tahay muraayad isku dhafan ama muraayad isku dhafan ama muraayad togan.
(C) Awoodda muraayadda
P = 1/f = 1/0,3 = +3 Diopters
Xoogga ama awoodda muraayadda waa +3 D. Calaamadda togan waxay ka dhigan tahay in muraayadda la isticmaalay ay tahay muraayad isku dhafan ama muraayad isku soo urursan.
