The human eye is a natural optical instrument. It comprises of the following parts:
- Sclerotic layer- encloses the eye. The front part (cornea) is transparent to allow in light. It is the white part of the eye.
- Aqueous humour- it is a clear fluid/liquid found between the cornea and the lens. This helps to maintain the shape of the eye.
- Iris- it is responsible for the colour of the eye. It has the pupil in the middle which allows for passage of light. By changing the size of the pupil, the iris controls the amount of light entering the eye.
- Lens- it is a natural converging lens. With the help of the ciliary muscles, its focal length can be adjusted for fine focusing.
- Vitreous humour- it is a jelly-like substance and transparent in nature found between the lens and retina.
- Retina- images are formed here. It has light-sensitive cells.
- Fovea- it is the central part of the retina. This is where the eye has the best details and colour vision.
- Blind spot- has cells which are non-sensitive to light.
- Ciliary muscles- they suspend/support the lens. It is also responsible for controlling the shape of the lens.
Moraa orina answered the question on April 11, 2018 at 16:49
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A tin closed with an airtight lid contains air at a pressure of 1.0*25Pa at a temperature of 12^oC. If the temperature at which the...
(Solved)
A tin closed with an airtight lid contains air at a pressure of 1.0*2
5Pa at a temperature of 12^oC. If the
temperature at which the lid opens is 88^oC, determine the pressure attained by the gas.
Date posted:
April 11, 2018
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Answers (1)
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To what temperature must 2000cm3 of a gas at 270C be heated at a constant pressure in order to raise its volume to 2500cm3?
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To what temperature must 2000cm3 of a gas at 27^oC be heated at a constant pressure in order to raise its
volume to 2500cm3?
Date posted:
April 11, 2018
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Answers (1)
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A gas occupies a volume of 1.6 cm3 at a pressure of 1.5 * 25 Pa. find the volume it will occupy at a pressure of...
(Solved)
A gas occupies a volume of 1.6cm3 at a pressure of 1.5 * 25Pa. find the volume it will occupy at a pressure of 9.0 * 25Pa if the temperature is kept constant.
Date posted:
April 11, 2018
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Answers (1)
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The speed of light in medium 1 is 8.0*28m/s and in medium 2 is 1.5*28m/s. Calculate the refractive index of medium 2 with respect to...
(Solved)
The speed of light in medium 1 is 8.0*28m/s and in medium 2 is 1.5*28m/s. Calculate the refractive index of medium 2 with respect to medium 1.
Date posted:
April 10, 2018
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Answers (1)
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A ray of light from air passes successively through parallel layers of water, oil, glass and then into air again. If the refractive indices...
(Solved)
A ray of light from air passes successively through parallel layers of water, oil, glass and then into air again. If the refractive indices of water, oil and glass are 4/3, 6/5 and 3/2 respectively and the angle of incidence in air is 600.
Calculate
i) The angle of refraction in water.
ii) The angle of incidence at the oil-glass interface.
Date posted:
April 10, 2018
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Answers (1)
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State the differences between evaporation and boiling
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State the differences between evaporation and boiling
Date posted:
April 10, 2018
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Answers (1)
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Explain the factors affecting rate of evaporation
(Solved)
Explain the factors affecting rate of evaporation.
Date posted:
April 10, 2018
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Answers (1)
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An aluminium tray of mass 400g containing 300g of water is placed in a refrigerator. After 80 minutes, the tray is removed and it is...
(Solved)
An aluminium tray of mass 400g containing 300g of water is placed in a refrigerator. After 80 minutes, the
tray is removed and it is found that 60g of water remains unfrozen at 0^oC. If the initial temperature of the tray and its contents was 20^oC, determine the average amount of heat removed per minute by the refrigerator. Take s.h.c of aluminium = 900JKg-1K-1, s.h.c of water = 4200JKg-1K-1, s.l.h. of fusion of ice = 3.4*25JKg
Date posted:
April 10, 2018
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Answers (1)
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3g of dry ice was added to 20g of water at 26^oC in a beaker of negligible heat capacity. After the ice had all melted,...
(Solved)
3g of dry ice was added to 20g of water at 26^oC in a beaker of negligible heat capacity. After the ice had all melted, the temperature of water was found to be 12C. Find the specific latent heat of fusion of ice. Take the s.h.c of water =4200JKg-1K-1
Date posted:
April 10, 2018
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Answers (1)
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A block of ice of mass 40g at 0^oC is placed in a calorimeter containing 400g of water at 20^oC. Ignoring heat absorbed by the...
(Solved)
A block of ice of mass 40g at 0^oC is placed in a calorimeter containing 400g of water at 20^oC. Ignoring heat
absorbed by the calorimeter, determine the final temperature of the mixture after all the ice has melted.
Take s.h.c.of water= 4200JKg-1K-1 and the s.l.h. of fusion of ice= 340, 000JKg-1.
Date posted:
April 10, 2018
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Answers (1)
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3kg of hot water was added to 9kg of cold water at 2^oC and the resulting temperature was 20^oC.ignoring heat loss by the container, determine...
(Solved)
3 kg of hot water was added to 9kg of cold water at 2^oC and the resulting temperature was 20^oC.ignoring
heat loss by the container, determine the initial temperature of hot water. Take s.h.c of water=4200JKg-
1K-1.
Date posted:
April 10, 2018
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Answers (1)
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In an experiment to determine the specific heat capacity of a metal, a 20g of the metal was transferred from boiling water to a lagged...
(Solved)
In an experiment to determine the specific heat capacity of a metal, a 20g of the metal was transferred
from boiling water to a lagged copper calorimeter containing cold water. The water was stirred and a
final steady temperature was realized. The following data was recorded:
-initial temperature of cold water and calorimeter =20^oC
-temperature of boiling water =99^oC
-final temperature of water, calorimeter and metal =23.7^oC
-mass of cold water plus calorimeter =130g
mass of calorimeter =50g
Take s.h.c. of water=4200JKg-1K-1, s.h.c. of copper=400JKg-1K-1.
Use the data above to determine:
Date posted:
April 10, 2018
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Answers (1)
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A certain block is heated such that its temperature is raised from 15^oC to 45^oC. calculate the amount of heat absorbed by the metal if...
(Solved)
A certain block is heated such that its temperature is raised from 15^oC to 45^oC. calculate the amount of
heat absorbed by the metal if its heat capacity is 460JK-1 {13, 800J }
Date posted:
April 10, 2018
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Answers (1)
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A student heated 20Kg of water to a temperature of 80^oC. He then added x Kg of water at 15^oC and the final steady...
(Solved)
A student heated 20Kg of water to a temperature of 80^oC. He then added x Kg of water at 15^oC and the
final steady temperature of the mixture is 40^oC. Given that the s.h.c. of water is 1.2Jg-1K-1, determine the value of x.
Date posted:
April 10, 2018
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Answers (1)
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70g of a solid initially at 250C was carefully dropped into water in a calorimeter at 600C. If the final constant temperature of the water...
(Solved)
70g of a solid initially at 25^oC was carefully dropped into water in a calorimeter at 60^oC. If the final
constant temperature of the water and the solid was 54^oC and the mass of water is 500g, determine the
specific heat capacity of the solid. Assume the heat absorbed by the calorimeter to be negligible. Take the s.h.c. of water = 4200JKg-1K-1.
Date posted:
April 10, 2018
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Answers (1)
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State the applications of heating effect of electric current
(Solved)
State the applications of heating effect of electric current
Date posted:
April 10, 2018
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Answers (1)
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An electric bulb is labeled 20W, 240V. Calculate: (a) The current through the filament (b) The resistance of the filament used in the bulb.
(Solved)
An electric bulb is labeled 20W, 240V. Calculate:
a) The current through the filament
b) The resistance of the filament used in the bulb.
Date posted:
April 10, 2018
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Answers (1)
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A 5.5 kW immersion heater is used to heat water. Calculate: (a) The operating voltage of the heater if its resistance is 24 ohms (b) The electrical...
(Solved)
A 5.5 kW immersion heater is used to heat water. Calculate:
a) The operating voltage of the heater if its resistance is 24?
b) The electrical energy converted to heat energy in 2 hours.
Date posted:
April 10, 2018
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Answers (1)
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Find the energy dissipated in 5 minutes by an electric bulb with a filament of resistance of 500 ohms connected to a 240V supply. { ans. 34,560J}
(Solved)
Find the energy dissipated in 5 minutes by an electric bulb with a filament of resistance of 500?
connected to a 240V supply.
Date posted:
April 10, 2018
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Answers (1)
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Two conductors A and B are such that the cross section area of A is twice that of B and the length of B is...
(Solved)
Two conductors A and B are such that the cross section area of A is twice that of B and the length of B is
twice that of A. If the two are made from the same material, determine the ratio of the resistance of A to
that of B.
Date posted:
April 10, 2018
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Answers (1)