1. Ubude obuqondile be- ilensi egobile (ilensi ejikelezayo) engu-30 cm. Into ephakeme ngo-5 cm itholakala ngakwesobunxele selensi. Nquma ibanga lesithombe, ukukhuliswa kwesithombe, ukuphakama kwesithombe kanye nezakhiwo zesithombe uma into ingama-15 cm ukusuka kulensi egobile.
Ingxoxo
I-Diketahui :
Ubude be-focal (f) = -30 cm
Ubude be-focal lens egobile buyi-negative ngoba indawo egobile yelens egobile ayidluliswanga yi-light beam noma i-virtual.
Ukuphakama kwento (h) = 5 cm
Ibanga lento = 15 cm
Kubuziwe : Ibanga lesithombe (s'), ukukhuliswa kwesithombe (M), ukuphakama kwesithombe (h') kanye nezakhiwo zesithombe
Jawab :
Isithombe sokwakheka kwesithombe sento ngelensi egobile:
Ibanga lesithombe (s'):
1/s' = 1/f – 1/s = -1/30 – 1/15 = -1/30 – 2/30 = -3/30
s' = -30/3 = -10 cm
Ibanga elibi lesithunzi lisho ukuthi isithunzi sibonakala noma asidluliswanga yimisebe yokukhanya.
Ibanga lesithombe elingama-10 cm lincane kunebanga lento elingama-15 cm.
Ukukhulisa isithombe (M):
M = -s'/s = -(-10)/15 = 10/15 = 2/3 izikhathi
Ukukhulisa isithombe kahle kusho ukuthi isithombe siqondile noma asiguqukile.
Usayizi wesithombe mncane ngokuphindwe kathathu kunosayizi wento.
Ukuphakama kwesithunzi (h'):
M = h'/h
h' = M h = (2/3)5 = 10/3 = 3,3 cm
Ukuphakama kwesithunzi kuhle, okusho ukuthi isithunzi siqondile noma asiphezulu.
Ukuphakama kwesithombe okungu-3,3 cm kuncane kunokuphakama kwento okungu-5 cm.
Izakhiwo zezithunzi
Ngokusekelwe ekubalweni okungenhla, kungaphethwa ngokuthi izakhiwo zesithombe sento eyakhiwe ilensi egobile yilezi:
– imisebe ebonakalayo noma yokukhanya ayidluli emthunzini
- iqonde noma ingagxilile phansi
– kuncishisiwe noma usayizi wesithombe mncane kunosayizi wento
– ibanga lesithombe lincane kunebanga lento
2. Into ephakeme ngamasentimitha ayi-10 ubude ingu-60 cm phambi kwelensi egobile enobude obuqondile obungu-30 cm. Bala ibanga lesithombe, ukukhuliswa kwesithombe, ukuphakama kwesithombe kanye nezakhiwo zesithombe!
Ingxoxo
I-Diketahui :
Ubude be-focal (f) = -30 cm
Ubude be-focal lens egobile buyi-negative ngoba indawo egobile yelens egobile ayidluliswanga yi-light beam noma i-virtual.
Ukuphakama kwento (h) = 10 cm
Ibanga lento = 60 cm
Kubuziwe : Ibanga lesithombe (s'), ukukhuliswa kwesithombe (M), ukuphakama kwesithombe (h') kanye nezakhiwo zesithombe
Jawab :
Isithombe sokwakheka kwesithombe sento ngelensi egobile:
Ibanga lesithombe (s'):
1/s' = 1/f – 1/s = -1/30 – 1/60 = -2/60 – 1/60 = -3/60
s' = -60/3 = -20 cm
Ibanga elibi lesithunzi lisho ukuthi isithunzi sibonakala noma asidluliswanga yimisebe yokukhanya.
Ibanga lesithombe elingama-20 cm lincane kunebanga lento elingama-60 cm.
Ukukhulisa isithombe (M):
M = -s'/s = -(-20)/60 = 20/60 = 1/3 izikhathi
Ukukhulisa isithombe kahle kusho ukuthi isithombe siqondile noma asiguqukile.
Usayizi wesithombe mncane ngokuphindwe kathathu kunosayizi wento.
Ukuphakama kwesithunzi (h'):
M = h'/h
h' = M h = (1/3)10 = 10/3 = 3,3 cm
Ukuphakama kwesithunzi kuhle, okusho ukuthi isithunzi siqondile noma asiphezulu.
Ukuphakama kwesithombe okungu-3,3 cm kuncane kunokuphakama kwento okungu-10 cm.
Izakhiwo zezithunzi
Ngokusekelwe ekubalweni okungenhla, kungaphethwa ngokuthi izakhiwo zesithombe sento eyakhiwe ilensi egobile yilezi:
– imisebe ebonakalayo noma yokukhanya ayidluli emthunzini
- iqonde noma ingagxilile phansi
– kuncishisiwe noma usayizi wesithombe mncane kunosayizi wento
– ibanga lesithombe lincane kunebanga lento
Inkinga yelensi egobile
1. Ilensi egobile inobude obuqondile obungu-20 cm kanti into ephakeme ngo-10 cm itholakala ebangeni elingu-10 cm phambi kwelensi egobile. Thola ibanga lesithombe, ukukhuliswa kwesithombe, ukuphakama kwesithombe kanye nezakhiwo zesithombe!
Ukhiye wempendulo:
(a) s' = -20/3 cm
(b) m = 2/3
(c) h' = 20/3 cm
(d) izakhiwo zesithombe: ezibonakalayo, eziqondile, ezincishisiwe ngosayizi
2. Bala ibanga lesithombe, ukukhuliswa kwesithombe, ukuphakama kwesithombe kanye nezakhiwo zesithombe sento engama-5 cm ukuphakama kanye nama-50 cm phambi kwelensi egobile enobude obuqondile obungama-40 cm!
Ukhiye wempendulo:
(a) s' = -22,2 cm
(b) m = 0,44
(c) h' = 2,2 cm
(d) izakhiwo zesithombe: ezibonakalayo, eziqondile, ezincishisiwe ngosayizi
