1.
What type of lens converges light?
Correct Answer
A. Convex
Explanation
A convex lens converges light because it is thicker in the middle than at the edges. When light rays pass through, the curvature of the lens causes the rays to bend towards the center line or axis. This convergence of light rays is what enables a convex lens to focus light on a single point, forming real images of objects placed at certain distances. This focusing ability is crucial for applications like magnifying glasses, cameras, and corrective eyewear for hyperopia, where a need exists to converge light rays for clearer vision or image formation.
2.
Which mirror type diverges light?
Correct Answer
A. Convex
Explanation
A convex mirror diverges light because its reflective surface bulges outward. When light rays strike the outward-curved surface, they reflect outward, causing them to spread apart. This diverging effect is useful in situations where a wider field of view is required. Convex mirrors do not focus light like lenses but instead, spread it over a broader area. This characteristic makes convex mirrors ideal for use in vehicle side mirrors and security systems in stores, where seeing as much area as possible is more beneficial than detailed image clarity.
3.
What mirror forms a real image?
Correct Answer
B. Concave
Explanation
A concave mirror forms real images by converging light rays that reflect off its inwardly curved surface. When parallel light rays hit a concave mirror, they reflect and converge at a focal point in front of the mirror. This property allows concave mirrors to form real, inverted images when the object is placed beyond the focal length. This capability is vital in devices like reflecting telescopes and automotive headlights, where focusing light into a beam or forming detailed images from great distances is essential.
4.
Which lens would you use to correct myopia?
Correct Answer
B. Concave
Explanation
A concave lens is used to correct myopia or nearsightedness. A myopic eye focuses light in front of the retina instead of directly on it, blurring distant objects. A concave lens, being thinner in the middle than at the edges, diverges light rays before they enter the eye. This divergence pushes the focal point of incoming light backward, aligning it more closely with the retina and thereby clarifying the vision of distant objects. This corrective measure helps achieve a clearer image for those with myopia, enabling them to see distant objects more sharply.
5.
What type of mirror is used in car side mirrors?
Correct Answer
A. Convex
Explanation
Convex mirrors are used in car side mirrors because they provide a wider field of view than flat mirrors. The outward curvature of a convex mirror allows it to reflect light from a broader area, helping drivers see more of their surroundings in a single glance. This wide-angle view is crucial for safety on the road, as it helps drivers detect vehicles, pedestrians, or obstacles that a flat mirror might miss, especially in the blind spots beside and slightly behind the vehicle.
6.
Which lens is thicker at the center than the edges?
Correct Answer
A. Convex
Explanation
A convex lens is thicker at the center than at the edges, a design that allows it to converge light rays effectively. This thickness at the center causes light rays passing through the edges to bend more sharply towards the axis than those passing near the center. The result is that all light rays that enter the lens converge at a point called the focal point. This ability to focus light makes convex lenses critical in applications where magnification or precise light manipulation is required, such as in microscopes, cameras, and optical telescopes.
7.
What mirror is used in telescopes to gather light?
Correct Answer
B. Concave
Explanation
Concave mirrors are used in telescopes to gather light due to their ability to converge light rays to a focal point. The inward curve of a concave mirror reflects light rays that strike it from vast distances, focusing them into a smaller, concentrated area. This concentration of light allows telescopes to collect more light from faint celestial objects, making them visible and highly detailed when observed through the telescope’s eyepiece. This capability is essential for astronomical observations, where capturing as much light as possible from distant stars and galaxies is crucial for study and exploration.
8.
Which lens forms a virtual image?
Correct Answer
B. Concave
Explanation
A concave lens forms virtual images because it causes light rays to diverge. When an object is viewed through a concave lens, the light rays from the object spread out before reaching the viewer’s eye, making the object appear to be positioned at a different location than it actually is. This location is behind the lens, and because the light rays never actually meet, the image cannot be projected onto a screen, hence it is called virtual. Concave lenses are used in specific optical devices where such virtual imaging is beneficial, including peepholes and some types of eyeglasses.
9.
What type of mirror is used in hallway safety?
Correct Answer
A. Convex
Explanation
Convex mirrors are used in hallway safety because they provide a panoramic view of the area. The curved surface reflects light from various angles, allowing a single mirror to reveal much of the hallway. This broad coverage helps prevent collisions and accidents in tight spaces, especially in corners and intersections where visibility is limited. The use of convex mirrors enhances safety by allowing individuals to see others approaching from various angles, reducing the risk of surprise encounters and allowing for smoother, safer movement in shared spaces.
10.
Which lens would you use to correct hyperopia?
Correct Answer
A. Convex
Explanation
A convex lens is used to correct hyperopia or farsightedness. In hyperopic eyes, light rays focus behind the retina instead of directly on it, making nearby objects appear blurry. A convex lens, being thicker at the center, converges light rays so that they focus earlier, moving the focal point forward onto the retina. This adjustment allows individuals with hyperopia to see nearby objects more clearly, enhancing their overall visual acuity for tasks such as reading, writing, or any other activity that involves close-up vision.