Read the following passage and answer the questions below - Leaving Cert Physics - Question 11 - 2019
Question 11
Read the following passage and answer the questions below.
One of the most common sights anywhere in the world are eyeglasses. Since we depend so much on the lenses... show full transcript
Worked Solution & Example Answer:Read the following passage and answer the questions below - Leaving Cert Physics - Question 11 - 2019
Step 1
Name the part of the eye where an image is formed.
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Answer
The part of the eye where an image is formed is the retina.
Step 2
What is the function of the pupil?
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Answer
The pupil regulates the amount of light entering the eye, allowing the lens to focus correctly on the retina.
Step 3
The eye can focus light from both nearby and distant objects. Describe how the eye allows itself for this to happen.
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Answer
The eye focuses light using the ciliary muscles and the lens. When viewing distant objects, the ciliary muscles relax, allowing the lens to flatten. For nearby objects, the ciliary muscles contract, thickening the lens to increase its refractive power.
Step 4
Name two the most common eye defects.
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What type of lens corrects short sightedness? Draw a sketch of this lens.
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Answer
A diverging lens corrects short sightedness.
(The sketch represents a diverging lens, which is thinner at the center than at the edges.)
Step 6
Copy the diagram below into your answerbook and complete the ray diagram to form a real image.
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Answer
(Provide a ray diagram showing a real image formed by a converging lens.)
Step 7
The power required to clearly view a nearby object is 38 m–1. A person with an eye defect has a maximum power of 32 m–1. Calculate the power of the lens required to correct this defect? What is the focal length of this lens?
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Answer
The power of the lens required can be found by subtracting the maximum power of the person from the required power: P=38extm−1−32extm−1=6extm−1
To find the focal length (f) of the lens, we use the formula: P = rac{1}{f}
Thus, f = rac{1}{P} = rac{1}{6 ext{ m}^{-1}} = 0.1667 ext{ m} = 16.67 ext{ cm}
Step 8
Light undergoes refraction as it passes through a lens. What is meant by refraction?
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Answer
Refraction is the bending of light rays as they pass from one medium to another, caused by a change in speed due to a difference in density between the two media.
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