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An optician tested the eyesight of 240 people - Edexcel - GCSE Biology - Question 4 - 2023 - Paper 1
Question 4
An optician tested the eyesight of 240 people. 35% of these people could read the normal vision row without wearing glasses. The rest of the people need glasses to... show full transcript
Worked Solution & Example Answer:An optician tested the eyesight of 240 people - Edexcel - GCSE Biology - Question 4 - 2023 - Paper 1
Step 1
Calculate the number of people who need glasses to correct their vision.
Answer
To find the number of people who need glasses, we first calculate the number of people who can read without glasses. This is given as 35% of 240.
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Calculate the number of people with normal vision:
240 × 0.35 = 84
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Now, subtract this number from the total number of people tested:
240 - 84 = 156
Thus, 156 people need glasses to correct their vision.
Step 2
Which diagram shows how short-sightedness can be corrected?
Answer
The diagram that shows how short-sightedness can be corrected is the one that depicts a diverging lens, which allows light rays to focus directly on the retina. Typically, this is represented as either the diagram labeled B or C from Figure 5. The correct answer should indicate the diverging lens' function.
Step 3
Describe why a person with cataracts would see the image shown in Figure 6.
Answer
A person with cataracts experiences blurred vision because the lens of the eye becomes cloudy. This condition scatters the light entering the eye, resulting in distorted or unclear images. The clouding affects how light reaches the retina, causing subjects to appear fuzzy and less defined.
Step 4
Step 5
Describe how messages are sent from the brain to muscles.
Answer
Messages are sent from the brain to muscles through motor neurons. When a stimulus is detected, sensory information is processed in the brain, which then generates electrical impulses. These impulses travel down the motor neurons, reaching the target muscles. Upon arrival, neurotransmitters are released at the neuromuscular junction, stimulating muscle contraction and producing the desired motion.