Iji ghọta onyinyo nke ihe e ji oghere convex kpụọ, lelee ajụjụ na mkparịta ụka dị n'okpuru ebe a. N'ajụjụ a, a na-eche na ihe ahụ dị n'ebe dị anya site na oghere convex, mgbe ahụ, a na-akọwa nhazi nke onyinyo ihe ahụ site na oghere convex , anya nke onyonyo ahụ site na oghere convex na mmụba nke onyonyo ahụ site na oghere convex .
Lensi convex (lensi converging) nwere ogologo focal nke 20 cm. Ihe dị sentimita iri n'ịdị elu dị n'aka ekpe nke lensi ahụ. Chọpụta anya onyonyo ahụ, mmụba onyonyo ahụ, na ịdị elu onyonyo ahụ ma ọ bụrụ:
a) anya nke ihe ahụ site na lenzi convex pere mpe karịa ogologo lenzi convex (s < f),
b) anya nke ihe ahụ site na lenzi convex bụ otu ihe ahụ dịka ogologo lenzi convex (s = f),
c) anya nke ihe ahụ site na lenzi convex karịrị ogologo lenzi convex (s > f).
Mkparịta ụka
A maara :
Ogologo anya (f) nke oghere concave = 20 cm
Ogologo anya nke lenzi convex dị mma n'ihi na isi ihe anya nke lenzi convex dị adị ma ọ bụ na-agafe site na ìhè.
Ogologo ihe (h) = 10 cm
Jawab :
Ogologo ihe ahụ pere mpe karịa ogologo focal nke lensị convex (s > f)
Ka e were ya na anya dị n'etiti ihe dị iche iche bụ 5 cm, 10 cm na 15 cm.
a) Ọ bụrụ na anya ihe ahụ (s) = 5 cm
Anya onyonyo (s')
1/s' = 1/f – 1/s = 1/20 – 1/5 = 1/20 – 4/20 = -3/20
s' = -20/3 = -6,7 cm
Anya onyonyo na-adịghị mma pụtara onyonyo mebere emebe, ebe ìhè ọkụ anaghị agafe onyonyo ahụ.
Anya onyonyo nke 6,7 cm karịrị anya ihe nke 5 cm.
Mmụba onyonyo (M)
M = -s'/s = -(-6,7)/5 = 6,7/5 = 1,3
Mmụba nke onyonyo a karịrị 1, nke pụtara na onyonyo a buru ibu ma ọ bụ nha onyonyo a buru ibu karịa nha ihe ahụ.
Ogologo onyinyo (h')
Usoro mmụba onyinyo:
M = h'/h
h' = M h = (1,3)(10 cm) = 13 cm
Ogologo onyinyo ahụ dị mma, nke pụtara na onyinyo ahụ kwụ ọtọ.
b) Ọ bụrụ na anya nke ihe (s) ahụ = 10 cm
Anya onyonyo (s')
1/s' = 1/f – 1/s = 1/20 – 1/10 = 1/20 – 2/20 = -1/20
s' = -20/1 = -20 cm
Anya onyonyo na-adịghị mma pụtara onyonyo mebere emebe, ebe ìhè ọkụ anaghị agafe onyonyo ahụ.
Anya onyonyo nke 20 cm karịrị anya ihe nke 10 cm.
Mmụba onyonyo (M)
M = -s'/s = -(-20)/10 = 20/10 = 2
Mmụba nke onyonyo a karịrị 1, nke pụtara na onyonyo a buru ibu ma ọ bụ nha onyonyo a buru ibu karịa nha ihe ahụ.
Ogologo onyinyo (h')
Usoro mmụba onyinyo:
M = h'/h
h' = M h = (2)(10 cm) = 20 cm
Ogologo onyinyo ahụ dị mma, nke pụtara na onyinyo ahụ kwụ ọtọ.
c) Ọ bụrụ na anya nke ihe (s) ahụ = 15 cm
Anya onyonyo (s')
1/s' = 1/f – 1/s = 1/20 – 1/15 = 3/60 – 4/60 = -1/60
s' = -60/1 = -60 cm
Anya onyonyo na-adịghị mma pụtara onyonyo mebere emebe, ebe ìhè ọkụ anaghị agafe onyonyo ahụ.
Anya onyonyo nke 60 cm karịrị anya ihe nke 15 cm.
Mmụba onyonyo (M)
M = -s'/s = -(-60)/15 = 60/15 = 4
Mmụba nke onyonyo a karịrị 1, nke pụtara na onyonyo a buru ibu ma ọ bụ nha onyonyo a buru ibu karịa nha ihe ahụ.
Ogologo onyinyo (h')
Usoro mmụba onyinyo:
M = h'/h
h' = M h = (4)(10 cm) = 40 cm
Ogologo onyinyo ahụ dị mma, nke pụtara na onyinyo ahụ kwụ ọtọ.
Ogologo ihe ahụ dị ka ogologo lensị convex (s = f)
Onyinyo ahụ dị n'ebe dị anya na-enweghị ngwụcha.
Ogologo ihe ahụ karịrị ogologo lensị convex (s > f)
Ka e were ya na anya dị n'etiti ihe dị iche iche bụ 30 cm, 40 cm na 50 cm.
a) Ọ bụrụ na anya ihe ahụ (s) = 30 cm
Anya onyonyo (s')
1/s' = 1/f – 1/s = 1/20 – 1/30 = 3/60 – 2/60 = 1/60
s' = 60/1 = 60 cm
Anya dị mma nke onyonyo pụtara ezigbo onyonyo, ebe ìhè na-agafe na onyonyo ahụ.
Anya onyonyo nke 60 cm karịrị anya ihe nke 30 cm.
Mmụba onyonyo (M)
M = -s'/s = -60/30 = -2
Mmụba nke onyonyo a karịrị 1, nke pụtara na onyonyo a buru ibu ma ọ bụ nha onyonyo a buru ibu karịa nha ihe ahụ.
Ogologo onyinyo (h')
Usoro mmụba onyinyo:
M = h'/h
h' = M h = (-2)(10 cm) = -20 cm
Ogologo onyinyo ahụ adịghị mma, nke pụtara na onyinyo ahụ agbanweela.
b) Ọ bụrụ na anya nke ihe (s) ahụ = 40 cm
Anya onyonyo (s')
1/s' = 1/f – 1/s = 1/20 – 1/40 = 2/40 – 1/40 = 1/40
s' = 40/1 = 40 cm
Anya dị mma nke onyonyo pụtara ezigbo onyonyo, ebe ìhè na-agafe na onyonyo ahụ.
Anya onyinyo nke 40 cm bụ otu ihe ahụ dịka anya ihe nke 40 cm.
Mmụba onyonyo (M)
M = -s'/s = -40/40 = -1
Mmụba nke onyonyo ahụ hà nhata 1, nke pụtara na nha onyonyo ahụ bụ otu nha nke ihe ahụ.
Ogologo onyinyo (h')
Usoro mmụba onyinyo:
M = h'/h
h' = M h = (-1)(10 cm) = -10 cm
Ogologo onyinyo ahụ adịghị mma, nke pụtara na onyinyo ahụ agbanweela.
b) Ọ bụrụ na anya nke ihe (s) ahụ = 50 cm
Anya onyonyo (s')
1/s' = 1/f – 1/s = 1/20 – 1/50 = 5/100 – 2/100 = 3/100
s' = 100/3 = 33,3 cm
Anya dị mma nke onyonyo pụtara ezigbo onyonyo, ebe ìhè na-agafe na onyonyo ahụ.
Anya onyonyo nke 33,3 cm pere mpe karịa anya ihe nke 50 cm.
Mmụba onyonyo (M)
M = -s'/s = -33,3/40 = -0,8
Mmụba nke onyonyo ahụ erughị 1, nke pụtara na nha onyonyo ahụ pere mpe karịa nha ihe ahụ.
Ogologo onyinyo (h')
Usoro mmụba onyinyo:
M = h'/h
h' = M h = (-0,8)(10 cm) = -8 cm
Ogologo onyinyo ahụ adịghị mma, nke pụtara na onyinyo ahụ agbanweela.
