Florida Teacher Certification Examinations (FTCE) Subject Area Practice Test

What is the purpose of a convex lens in the eyepiece of a telescope?

1. Diverge the rays to disperse light

2. Converge the rays for directed viewing

3. Filter unwanted light

4. Magnify distant objects

The correct answer is: Converge the rays for directed viewing

The purpose of a convex lens in the eyepiece of a telescope is to converge the rays of light entering the telescope so that they come together at a focal point, allowing for directed viewing of distant objects. When light rays pass through a convex lens, they bend inward and focus at a specific point, which enhances the clarity and detail of the image being viewed. This convergence is essential for allowing the viewer to see a magnified and well-defined image of the distant object, such as a star or planet. Magnification involves not just the physical properties of the lens but also how images are produced and perceived through the arrangement of the telescope's components. The eyepiece lens works in conjunction with the telescope's primary lens or mirror, which collects light from distant objects, ensuring that the light is focused properly for optimal viewing. While the options surrounding filtering light or diverging rays do involve lenses, they do not accurately describe the primary function of the convex lens in the eyepiece, which is central to the process of creating a clear, directed image.