Ukuze uqonde isithombe sento eyakhiwe ilensi eqondile, hlola isibonelo esilandelayo sombuzo kanye nengxoxo. Kulo mbuzo, kucatshangwa ukuthi into ikude kakhulu nelensi eqondile, bese kuchazwa ukwakheka kwesithombe. isithombe sento ngelensi eqondile, ibanga lesithombe kusuka kulensi eqondile kanye nokukhulisa isithombe nge ilensi eqondile
Ilensi egoqekile (ilensi ehlanganayo) inobude obuqondile obungu-20 cm. Into ephakeme ngo-10 cm itholakala ngakwesobunxele selensi. Nquma ibanga lesithombe, ukukhuliswa kwesithombe, kanye nokuphakama kwesithombe uma:
a) ibanga lento kusukela kulensi eqondile lincane kunobude obuqondile belensi eqondile (s < f),
b) ibanga lento kusukela kulensi eqondile lifana nobude obuqondile belensi eqondile (s = f),
c) ibanga lento ukusuka kulensi eqondile likhulu kunobude obuqondile belensi eqondile (s > f).
Ingxoxo
I-Diketahui :
Ubude be-focal (f) belensi egobile = 20 cm
Ubude be-focal lens eqondile buyinto enhle ngoba indawo eqondile yelens eqondile ingokoqobo noma idlula ngokukhanya okukhulu.
Ukuphakama kwento (h) = 10 cm
Jawab :
Ibanga lento lincane kunobude bokugxila belensi eqondile (s > f)
Ake sithi ibanga phakathi kwezinto lingu-5 cm, 10 cm kanye no-15 cm.
a) Uma ibanga (ama) lento = 5 cm
Ibanga lesithombe (s')
1/s' = 1/f – 1/s = 1/20 – 1/5 = 1/20 – 4/20 = -3/20
s' = -20/3 = -6,7 cm
Ibanga lesithombe elibi lisho isithombe esibonakalayo, lapho ukukhanya kungadluli khona esithombeni.
Ibanga lesithombe elingu-6,7 cm likhulu kunebanga lento elingu-5 cm.
Ukukhulisa isithombe (M)
M = -s'/s = -(-6,7)/5 = 6,7/5 = 1,3
Ukwandiswa kwesithombe kukhulu kuno-1, okusho ukuthi isithombe sikhulisiwe noma usayizi wesithombe mkhulu kunosayizi wento.
Ukuphakama kwesithunzi (h')
Ifomula yokukhulisa isithunzi:
M = h'/h
h' = M h = (1,3)(10 cm) = 13 cm
Ukuphakama kwesithunzi kuhle, okusho ukuthi isithunzi siqondile.
b) Uma ibanga lento (ama) = 10 cm
Ibanga lesithombe (s')
1/s' = 1/f – 1/s = 1/20 – 1/10 = 1/20 – 2/20 = -1/20
s' = -20/1 = -20 cm
Ibanga lesithombe elibi lisho isithombe esibonakalayo, lapho ukukhanya kungadluli khona esithombeni.
Ibanga lesithombe elingu-20 cm likhulu kunebanga lento elingu-10 cm.
Ukukhulisa isithombe (M)
M = -s'/s = -(-20)/10 = 20/10 = 2
Ukwandiswa kwesithombe kukhulu kuno-1, okusho ukuthi isithombe sikhulisiwe noma usayizi wesithombe mkhulu kunosayizi wento.
Ukuphakama kwesithunzi (h')
Ifomula yokukhulisa isithunzi:
M = h'/h
h' = M h = (2)(10 cm) = 20 cm
Ukuphakama kwesithunzi kuhle, okusho ukuthi isithunzi siqondile.
c) Uma ibanga lento (ama) = 15 cm
Ibanga lesithombe (s')
1/s' = 1/f – 1/s = 1/20 – 1/15 = 3/60 – 4/60 = -1/60
s' = -60/1 = -60 cm
Ibanga lesithombe elibi lisho isithombe esibonakalayo, lapho ukukhanya kungadluli khona esithombeni.
Ibanga lesithombe elingu-60 cm likhulu kunebanga lento elingu-15 cm.
Ukukhulisa isithombe (M)
M = -s'/s = -(-60)/15 = 60/15 = 4
Ukwandiswa kwesithombe kukhulu kuno-1, okusho ukuthi isithombe sikhulisiwe noma usayizi wesithombe mkhulu kunosayizi wento.
Ukuphakama kwesithunzi (h')
Ifomula yokukhulisa isithunzi:
M = h'/h
h' = M h = (4)(10 cm) = 40 cm
Ukuphakama kwesithunzi kuhle, okusho ukuthi isithunzi siqondile.
Ibanga lento lifana nobude be-focal belensi eqondile (s = f)
Isithunzi sisekude kakhulu.
Ibanga lento likhulu kunobude obuqondile belensi eqondile (s > f)
Ake sithi ibanga phakathi kwezinto lingu-30 cm, 40 cm kanye no-50 cm.
a) Uma ibanga (ama) lento = 30 cm
Ibanga lesithombe (s')
1/s' = 1/f – 1/s = 1/20 – 1/30 = 3/60 – 2/60 = 1/60
s' = 60/1 = 60 cm
Ibanga lesithombe elihle lisho isithombe sangempela, lapho ukukhanya kudlula khona esithombeni.
Ibanga lesithombe elingu-60 cm likhulu kunebanga lento elingu-30 cm.
Ukukhulisa isithombe (M)
M = -s'/s = -60/30 = -2
Ukwandiswa kwesithombe kukhulu kuno-1, okusho ukuthi isithombe sikhulisiwe noma usayizi wesithombe mkhulu kunosayizi wento.
Ukuphakama kwesithunzi (h')
Ifomula yokukhulisa isithunzi:
M = h'/h
h' = M h = (-2)(10 cm) = -20 cm
Ukuphakama kwesithunzi kuphambene, okusho ukuthi isithunzi siphendukezelwe.
b) Uma ibanga lento (ama) = 40 cm
Ibanga lesithombe (s')
1/s' = 1/f – 1/s = 1/20 – 1/40 = 2/40 – 1/40 = 1/40
s' = 40/1 = 40 cm
Ibanga lesithombe elihle lisho isithombe sangempela, lapho ukukhanya kudlula khona esithombeni.
Ibanga lesithunzi elingama-40 cm lifana nebanga lento elingama-40 cm.
Ukukhulisa isithombe (M)
M = -s'/s = -40/40 = -1
Ukukhulisa isithombe kulingana no-1, okusho ukuthi ubukhulu besithombe bufana nobukhulu bento.
Ukuphakama kwesithunzi (h')
Ifomula yokukhulisa isithunzi:
M = h'/h
h' = M h = (-1)(10 cm) = -10 cm
Ukuphakama kwesithunzi kuphambene, okusho ukuthi isithunzi siphendukezelwe.
b) Uma ibanga lento (ama) = 50 cm
Ibanga lesithombe (s')
1/s' = 1/f – 1/s = 1/20 – 1/50 = 5/100 – 2/100 = 3/100
s' = 100/3 = 33,3 cm
Ibanga lesithombe elihle lisho isithombe sangempela, lapho ukukhanya kudlula khona esithombeni.
Ibanga lesithombe elingama-33,3 cm lincane kunebanga lento elingama-50 cm.
Ukukhulisa isithombe (M)
M = -s'/s = -33,3/40 = -0,8
Ukukhulisa isithombe kungaphansi kuka-1, okusho ukuthi usayizi wesithombe mncane kunosayizi wento.
Ukuphakama kwesithunzi (h')
Ifomula yokukhulisa isithunzi:
M = h'/h
h' = M h = (-0,8)(10 cm) = -8 cm
Ukuphakama kwesithunzi kuphambene, okusho ukuthi isithunzi siphendukezelwe.
