Malapit at malayo ang paningin – mga problema at solusyon
1. Isang batang may nnakakakita ng pandinig kayang magbasa ng libro sa malapit na puntong 1 metro. Para makabasa sa normal na pagbasa layo na 25 cm, tukuyin ang lakas ng lente na dapat gamitin ng bata.
solusyon:
Nagdurusa ang bata farsighted, kung saan ang malapit na punto ng kanyang mga mata ay 1 metro o 100 cm. Ang malapit na punto ng normal na mata ay 25 cm. Ang mata ay maaaring gawing normal sa pamamagitan ng isang lente na may matambok na matambok.
Kilala:
Near point = image distance (s’) = -100 cm
The shadow must be in front of the convex lens so it can be seen. Because the shadow is in front of the convex lens then the image is virtual and signed negative.
Normal reading distance = object distance (s) = 25 cm
Karaniwan : power of lens
solusyon:
The focal length of the convex lens (f) :
1/f = 1/s + 1/s’ = 1/25 – 1/100 = 4/100 – 1/100 = 3/100
f = 100/3 cm
f = (100/3 : 100) m
f = (100/3 x 1/100) m
f = 1/3 m
The power of convex lens (P) :
P = 1 /f = 1 : 1/3 = 1 x 3/1 = 3 Diopters.
Power of convex lens is 3 diopters.
2.
Based on the above figure, determine the eye defect used to normalized the eye.
Solusyon
Eye defects: farsighted
The light beam can be focused precisely on the retina when a concave lens is placed in front of the eye. Divergent lenses help spread the beam of light so that it can be focused precisely on the retina.
3. Someone can read at the closest distance of 50 cm. In order for him to read at a distance of 30 cm, determine the power of the salamin sa mata lente
solusyon:
The person is suffering from malapit nang makita, the lenses used to normalize nearsighted eyes are convex lenses or convergent lenses or positive lenses.
In order for the observed object to be 30 cm in front of the eye, the lens should form an image at a distance of 50 cm in front of the eye. The image is in front of the lens so that the image is upright and virtual.
Kilala:
Object’s distance (s) = 30 sentimetro
Image’s distance (s’) = -50 cm (negative because virtual)
Hinahanap: Kapangyarihan ng lente (P)
solusyon:
Focal length :
1/f = 1/s + 1/s’
1/f = 1/30 + 1/-50
1/f = 5/150 – 3/150
1/f = 2/150
f = 150/2 = 75 cm = 0.75 meter = 75/100 meters
Focal length signed positive means the lens used is convex lens.
Power of lens :
P = 1/f
P = 1 : 75/100 = 1 x 100/75
P = 100/75
P = 4/3 Mga Diopter
