An eye condition is corrected using a +4.0D lens - AQA - A-Level Physics - Question 1 - 2022 - Paper 5
Question 1
An eye condition is corrected using a +4.0D lens.
Which eye condition could be corrected by using this lens? Tick (✓) one box.
astigmatism
hypermetropia
myopia... show full transcript
Worked Solution & Example Answer:An eye condition is corrected using a +4.0D lens - AQA - A-Level Physics - Question 1 - 2022 - Paper 5
Step 1
Which eye condition could be corrected by using this lens?
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Answer
The condition that can be corrected using a +4.0D lens is hypermetropia. This type of refractive error occurs when distant objects can be seen clearly, but close ones do not come into proper focus.
Step 2
Calculate the magnification produced by the +4.0D lens when viewing an object 75 cm from this lens.
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Answer
To calculate the magnification ( ext{M}) produced by the lens, we can use the formula:
ext{M} = 1 + rac{d}{f}
where:
d = distance from the lens to the object = 75 cm = 0.75 m
f = focal length of the lens. Since the power (P) of the lens is related to the focal length by the formula: P = rac{1}{f}
Substituting the power of the lens:
+4.0D = rac{1}{f}, so the focal length f = rac{1}{P} = rac{1}{4} = 0.25 m.
Now substituting the values into the magnification formula: ext{M} = 1 + rac{0.75}{0.25} = 1 + 3 = 4.
Thus, the magnification produced by the lens is 4.
Step 3
Name of X
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Answer
X is the cornea.
Step 4
Primary optical function of X
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The primary optical function of the cornea is to refract (bend) light as it enters the eye.
Step 5
Name of Y
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Answer
Y is the lens.
Step 6
Primary optical function of Y
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Answer
The primary optical function of the lens is to control the focus of light by changing its shape in order to focus images on the retina.
Step 7
Name of Z
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Answer
Z is the iris.
Step 8
Primary optical function of Z
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The primary optical function of the iris is to control the amount of light entering the eye by adjusting the size of the pupil.
