Kuti unzwisise mufananidzo wechinhu chakagadzirwa ne lenzi ine convex, tarisa muenzaniso unotevera wemubvunzo nekukurukurirana. Mumubvunzo uyu, zvinofungidzirwa kuti chinhu chacho chiri kure ne lenzi ine convex, wobva watsanangura kuumbwa kwemufananidzo wechinhu chacho ne lenzi ine convex , daro remufananidzo kubva kune lenzi ine convex uye kukura kwemufananidzo ne lenzi ine convex .
Lenzi ine convex (lenzi inoungana) ine urefu hwemasendimita makumi maviri. Chinhu chakareba masendimita gumi chiri kuruboshwe rwelenzi. Sarudza daro remufananidzo, kukura kwemufananidzo, uye kukwirira kwemufananidzo kana:
a) kureba kwechinhu kubva kune lenzi ye convex kudiki pane kureba kwefocal ye lenzi ye convex (s < f),
b) kureba kwechinhu kubva kune lenzi yakapinza kwakafanana nehurefu hwegirazi rakapinza (s = f),
c) daro rechinhu kubva kune lenzi yakapinza rakakura kupfuura urefu hwefocal relenzi yakapinza (s > f).
Kukurukurirana
Zvinozivikanwa :
Kureba kwefocal (f) kwelenzi yakakombama = 20 cm
Kureba kwegirazi re convex kwakanaka nekuti nzvimbo yakatarisana negirazi re convex ndeyechokwadi kana kuti inopfuudzwa nechiedza.
Kureba kwechinhu (h) = 10 cm
Jawab :
Daro rechinhu diki pane urefu hwefocal relenzi ye convex (s > f)
Ngatitii daro rechinhu chacho riri 5 cm, 10 cm uye 15 cm.
a) Kana daro rechinhu (s) = 5 cm
Kureba kwemufananidzo (s')
1/s' = 1/f – 1/s = 1/20 – 1/5 = 1/20 – 4/20 = -3/20
s' = -20/3 = -6,7 cm
Kureba kwemufananidzo usina kunaka zvinoreva mufananidzo chaiwo, uko chiedza chisingapfuuri nepamufananidzo.
Kureba kwemufananidzo we6,7 cm kwakakura kupfuura kureba kwechinhu che5 cm.
Kukura kwemufananidzo (M)
M = -s'/s = -(-6,7)/5 = 6,7/5 = 1,3
Kukura kwemufananidzo kwakakura kupfuura 1, zvichireva kuti mufananidzo wacho wakakura kana kuti saizi yemufananidzo yakakura kupfuura saizi yechinhu chacho.
Kureba kwemumvuri (h')
Fomura yekuwedzera mumvuri:
M = h'/h
h' = M h = (1,3)(10 cm) = 13 cm
Kureba kwemumvuri kwakanaka, zvichireva kuti mumvuri wakamira.
b) Kana daro rechinhu (s) = 10 cm
Kureba kwemufananidzo (s')
1/s' = 1/f – 1/s = 1/20 – 1/10 = 1/20 – 2/20 = -1/20
s' = -20/1 = -20 cm
Kureba kwemufananidzo usina kunaka zvinoreva mufananidzo chaiwo, uko chiedza chisingapfuuri nepamufananidzo.
Kureba kwemufananidzo we20 cm kwakakura kupfuura kureba kwechinhu che10 cm.
Kukura kwemufananidzo (M)
M = -s'/s = -(-20)/10 = 20/10 = 2
Kukura kwemufananidzo kwakakura kupfuura 1, zvichireva kuti mufananidzo wacho wakakura kana kuti saizi yemufananidzo yakakura kupfuura saizi yechinhu chacho.
Kureba kwemumvuri (h')
Fomura yekuwedzera mumvuri:
M = h'/h
h' = M h = (2)(10 cm) = 20 cm
Kureba kwemumvuri kwakanaka, zvichireva kuti mumvuri wakamira.
c) Kana daro rechinhu (s) = 15 cm
Kureba kwemufananidzo (s')
1/s' = 1/f – 1/s = 1/20 – 1/15 = 3/60 – 4/60 = -1/60
s' = -60/1 = -60 cm
Kureba kwemufananidzo usina kunaka zvinoreva mufananidzo chaiwo, uko chiedza chisingapfuuri nepamufananidzo.
Kureba kwemufananidzo we60 cm kwakakura kupfuura kureba kwechinhu che15 cm.
Kukura kwemufananidzo (M)
M = -s'/s = -(-60)/15 = 60/15 = 4
Kukura kwemufananidzo kwakakura kupfuura 1, zvichireva kuti mufananidzo wacho wakakura kana kuti saizi yemufananidzo yakakura kupfuura saizi yechinhu chacho.
Kureba kwemumvuri (h')
Fomura yekuwedzera mumvuri:
M = h'/h
h' = M h = (4)(10 cm) = 40 cm
Kureba kwemumvuri kwakanaka, zvichireva kuti mumvuri wakamira.
Daro rechinhu rakafanana nehurefu hwefocal relenzi ye convex (s = f)
Mvuri uri kure zvikuru.
Kureba kwechinhu kwakakura kupfuura kureba kwefocal kwelenzi ye convex (s > f)
Ngatitii daro rechinhu chacho riri 30 cm, 40 cm uye 50 cm.
a) Kana daro rechinhu (s) = 30 cm
Kureba kwemufananidzo (s')
1/s' = 1/f – 1/s = 1/20 – 1/30 = 3/60 – 2/60 = 1/60
s' = 60/1 = 60 cm
Kureba kwemufananidzo wakanaka zvinoreva mufananidzo chaiwo, apo chiedza chinopfuura nepakati pemufananidzo.
Kureba kwemufananidzo we60 cm kwakakura kupfuura kureba kwechinhu che30 cm.
Kukura kwemufananidzo (M)
M = -s'/s = -60/30 = -2
Kukura kwemufananidzo kwakakura kupfuura 1, zvichireva kuti mufananidzo wacho wakakura kana kuti saizi yemufananidzo yakakura kupfuura saizi yechinhu chacho.
Kureba kwemumvuri (h')
Fomura yekuwedzera mumvuri:
M = h'/h
h' = M h = (-2)(10 cm) = -20 cm
Kureba kwemumvuri hakuna kunaka, zvichireva kuti mumvuri wakapinduka.
b) Kana daro rechinhu (s) = 40 cm
Kureba kwemufananidzo (s')
1/s' = 1/f – 1/s = 1/20 – 1/40 = 2/40 – 1/40 = 1/40
s' = 40/1 = 40 cm
Kureba kwemufananidzo wakanaka zvinoreva mufananidzo chaiwo, apo chiedza chinopfuura nepakati pemufananidzo.
Nharaunda yemumvuri ye40 cm yakafanana nedaro rechinhu che40 cm.
Kukura kwemufananidzo (M)
M = -s'/s = -40/40 = -1
Kukura kwemufananidzo kwakaenzana ne1, zvichireva kuti saizi yemufananidzo yakafanana nehukuru hwechinhu chacho.
Kureba kwemumvuri (h')
Fomura yekuwedzera mumvuri:
M = h'/h
h' = M h = (-1)(10 cm) = -10 cm
Kureba kwemumvuri hakuna kunaka, zvichireva kuti mumvuri wakapinduka.
b) Kana daro rechinhu (s) = 50 cm
Kureba kwemufananidzo (s')
1/s' = 1/f – 1/s = 1/20 – 1/50 = 5/100 – 2/100 = 3/100
s' = 100/3 = 33,3 cm
Kureba kwemufananidzo wakanaka zvinoreva mufananidzo chaiwo, apo chiedza chinopfuura nepakati pemufananidzo.
Kureba kwemufananidzo we33,3 cm kudiki pane kureba kwechinhu che50 cm.
Kukura kwemufananidzo (M)
M = -s'/s = -33,3/40 = -0,8
Kukura kwemufananidzo kudiki pane 1, zvichireva kuti saizi yemufananidzo idiki pane saizi yechinhu chiripo.
Kureba kwemumvuri (h')
Fomura yekuwedzera mumvuri:
M = h'/h
h' = M h = (-0,8)(10 cm) = -8 cm
Kureba kwemumvuri hakuna kunaka, zvichireva kuti mumvuri wakapinduka.
