A photographer uses a camera and a human eye to explain image formation to a class. Fig. 1 shows a simplified section of the human eye when viewing a nearby...
Question 1 Report
A photographer uses a camera and a human eye to explain image formation to a class. Fig. 1 shows a simplified section of the human eye when viewing a nearby insect. The ciliary muscles are shown around the lens. For the insect to be seen clearly, the lens must bend light strongly enough to form an image on the retina. The student compares this process with focusing a camera lens.
(a) Name the parts labelled V and W. [2]
(b) Describe the change in the lens when the person changes focus from a distant building to the nearby insect. [2]
(c) Explain how the ciliary muscles cause this lens change. [3]
(d) Explain why a focused image must form on X for the insect to be seen clearly. [2]
(e) State the name of the process by which the eye changes focus. [1]
(f) Complete this sentence. Nerve impulses from the eye travel to the __________ in the brain. [1]
Answer Details
(a) V is the lens and W is the ciliary muscles. [2]
(b) Changing focus from a distant building to a nearby insect makes the lens become thicker or more rounded. It therefore becomes more strongly convex. [2]
(c) The ciliary muscles contract. This decreases the tension in the suspensory ligaments, allowing the elastic lens to become thicker. [3]
(d) X is the retina. A focused image must form there because the retina contains light receptor cells. These cells convert light energy into nerve impulses that are sent to the brain. [2]
(e) The process of changing focus is called accommodation. [1]
(f) Nerve impulses travel to the visual cortex in the brain. [1]
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