Maqaal ku saabsan Samaynta sawirka iyadoo la adeegsanayo muraayad kala duwan (lens concave)
Si aad u fahamto sameynta sawirka ee muraayadda qaloocan, fiiri dhibaatooyinka iyo xalalka tusaalaha soo socda. Xaaladdan, shayga waxaa loo maleynayaa inuu ku jiro masaafo gaar ah muraayadda qaloocan,
ka dibna sawir qaab-dhismeedka sawirka muraayadda qaloocan, masaafada sawirka laga soo bilaabo muraayadda qaloocan iyo weynaynta sawirka muraayadda qaloocan.
Dhererka diiradda ee muraayadda qaloocan (muraayadda kala leexata) waa 20 cm. Walxaha dhererka 10 cm ah waxay ku yaalliin bidixda muraayadda. Go'aami masaafada sawirka, weynaynta sawirka iyo dhererka sawirka, haddii:
a) masaafada walaxdu ay ka yar tahay dhererka diiradda ee muraayadda qaloocan
b) masaafada walaxdu waxay la mid tahay dhererka diiradda ee muraayadda qaloocan
c) masaafada shayga ayaa ka weyn dhererka diiradda ee muraayadda qaloocan
La yaqaan
Dhererka diiradda ee muraayadda qaloocan (f) = -20 cm
Dhererka diiradda ee muraayadda qaloocan waxay leedahay calaamad taban sababtoo ah barta diiradda ee muraayadda qaloocan waa mid casri ah, halkaas oo iftiinka iftiinku uusan ka gudbin barta diiradda.
Dhererka shayga (h) = 10 cm
Solution:
Masaafada shayga ayaa ka yar dhererka diiradda ee muraayadda qaloocan (samee > f)
Ka soo qaad in masaafada shaygu tahay 5 cm, 10 cm iyo 15 cm.
a) Dhererka diiradda waa -20 cm haddii masaafada shayga (same) = 5 cm
Masaafada sawirka (di)
1/di = 1/f – 1/do = -1/20 – 1/5 = -1/20 – 4/20 = -5/20
di = -20/5 = -4 cm
Calaamadda masaafada sawirka, taban, macnaheedu waa sawirku waa mid casri ah, halkaas oo iftiinka iftiinku uusan dhex marin sawirka.
Masaafada sawirka, 4 cm, way ka yar tahay masaafada shayga, 5 cm.
Weyneynta sawirka (M)
M = -di / samee = -(-4)/5 = 4/5 = 0.8
Weyneynta sawirka oo ka yar 1 waxay la macno tahay in sawirka la dhimay, ama cabbirka sawirku uu ka yar yahay cabbirka shayga.
Dhererka sawirka (h')
Isle'egta weyneynta sawirka:
M = h' / h
h' = M h = (0.8)(10 cm) = 8 cm
Dhererka sawirku waa calaamad wanaagsan, taasoo la micno ah in sawirku uu toosan yahay.
b) Dhererka diiradda waa -20 cm iyo haddii masaafada shayga (do) = 10 cm
Masaafada sawirka (di)
1/di = 1/f – 1/do = -1/20 – 1/10 = -1/20 – 2/20 = -3/20
di = -20/3 = -6.7 cm
Masaafada sawirku waa taban, taasoo la macno ah in sawirku yahay mid casri ah, halkaas oo iftiinka iftiinku uusan dhex marin sawirka.
Masaafada sawirka waa 6.7 cm, ka yar masaafada shayga, 10 cm.
Weyneynta sawirka (M)
M = -di / samee = -(-6.7)/10 = 6.7 / 10 = 0.67
Weyneynta sawirku waxay ka yar tahay 1 macnaheedu waa in sawirku uu yaraaday, ama cabbirka sawirku uu ka yar yahay cabbirka shayga.
Dhererka sawirka (h')
Isle'egta weyneynta sawirka:
M = h'/saacaddii
h' = M h = (0.67)(10 cm) = 6.7 cm
Dhererka sawirku waa calaamad wanaagsan, taasoo la micno ah in sawirku uu toosan yahay.
c) Dhererka diiradda waa -20 cm iyo masaafada shayga (do) = 15 cm
Masaafada sawirka (di)
1/di = 1/f – 1/do = -1/20 – 1/15 = -3/60 – 4/60 = -7/60
di = -60/7 = -8.6 cm
Masaafada sawirku waa taban, taasoo la macno ah in sawirku yahay mid casri ah, halkaas oo iftiinka iftiinku uusan dhex marin sawirka.
Masaafada sawirka waa 8.7 cm, ka yar masaafada shayga, 15 cm.
Weyneynta sawirka (M)
M = -di / samee = -(-8.6)/10 = 8.6 / 10 = 0.86
Weyneynta sawirka oo ka yar 1 waxay la macno tahay in cabbirka sawirku uu ka yar yahay cabbirka shayga.
Dhererka sawirka (h')
Isle'egta weyneynta sawirka:
M = h'/saacaddii
h' = M h = (0.86)(10 cm) = 8.6 cm
Dhererka sawirku waa mid togan, taasoo la macno ah in sawirku uu toosan yahay.
Masaafada shayga waxay la mid tahay dhererka diiradda ee muraayadda qaloocan (do = f)
Dhererka diiradda (f) = masaafada shayga (do) = 20 cm.
Masaafada sawirka (di)
1/di = 1/f – 1/do = -1/20 – 1/20 = -2/20 = -2/20
di = -20/2 = -10 cm
Masaafada sawirku waa taban, taasoo la macno ah in sawirku yahay mid casri ah, halkaas oo iftiinka iftiinku uusan dhex marin sawirka.
Masaafada sawirka waa 10 cm, ka yar masaafada shayga, 20 cm.
Weyneynta sawirka (M)
M = -di / samee = -(-10)/20 = 10/20 = 0.5
Weyneynta sawirka waa ka yar tahay 1, taasoo la micno ah in cabbirka sawirku uu ka yar yahay cabbirka shayga.
Dhererka sawirka (h')
Isle'egta weyneynta sawirka:
M = h'/saacaddii
h' = M h = (0.5)(10 cm) = 5 cm
Dhererka sawirku waa mid togan, taasoo la macno ah in sawirku uu toosan yahay.
Masaafada shayga ayaa ka weyn dhererka diiradda ee muraayadda qaloocan (samayn > f)
Ka soo qaad in masaafada walxaha ay tahay 30 cm iyo 40.
a) Dhererka diiradda waa -20 cm haddii masaafada shayga (same) = 30 cm
Masaafada sawirka (di)
1/di = 1/f – 1/do = -1/20 – 1/30 = -3/60 – 2/60 = -5/60
di = -60/5 = -12 cm
Masaafada sawirku waa taban, taasoo la macno ah in sawirku yahay mid casri ah, halkaas oo iftiinka iftiinku uusan dhex marin sawirka.
Masaafada sawirka waa 12 cm, ka yar masaafada shayga ee 30 cm.
Weyneynta sawirka (M)
M = -di / samee = -(-12)/30 = 12/30 = 0.4
Weyneynta sawirka waa ka yar tahay 1, taasoo la micno ah in cabbirka sawirku uu ka yar yahay cabbirka shayga.
Dhererka sawirka (h')
Isle'egta weyneynta sawirka:
M = h'/saacaddii
h' = M h = (0.4)(10 cm) = 4 cm
Dhererka sawirku waa calaamad wanaagsan, taasoo la micno ah in sawirku uu toosan yahay.
b) Dhererka diiradda -20 cm iyo haddii masaafada shayga (samee) = 40 cm
Masaafada sawirka (di)
1/di = 1/f – 1/do = -1/20 – 1/40 = -2/40 – 1/40 = -3/40
di = -40/3 = -13 cm
Masaafada sawirku waa taban, taasoo la macno ah in sawirku yahay mid casri ah, halkaas oo iftiinka iftiinku uusan dhex marin sawirka.
Masaafada sawirka waa 13 cm, ka yar masaafada shayga 40 cm.
Weyneynta sawirka (M)
M = -di / samee = -(-13)/40 = 13/40 = 0.3
Weyneynta sawirka waa ka yar tahay 1, taasoo la micno ah in cabbirka sawirku uu ka yar yahay cabbirka shayga.
Dhererka sawirka (h')
Isle'egta weyneynta sawirka:
M = h'/saacaddii
h' = M h = (0.3)(10 cm) = 3 cm
Dhererka sawirka waxaa lagu calaamadeeyay togan, taasoo la micno ah in sawirku uu toosan yahay.
