Final answer:
When a person with normal vision glances down to read the speedometer while driving, the lens of the eye adjusts its focal length through a process called accommodation. This allows the person to see the speedometer clearly, even though it is closer to their eyes than the objects they were looking at far ahead.
Step-by-step explanation:
When a person with normal vision glances down to read the speedometer while driving, the lens of the eye adjusts its focal length through a process called accommodation. This allows the person to see the speedometer clearly, even though it is closer to their eyes than the objects they were looking at far ahead.
The lens of the eye changes its shape to increase its refractive power, which brings the image of the speedometer onto the retina for clear vision.
This process of accommodation is automatic and allows people with normal vision to focus on objects at different distances without effort.