Test: Light: Mirrors and Lenses - Class 8 MCQ

A concave mirror has a reflecting surface that curves inward, resembling the inside of a bowl or the inner side of a spoon. This shape allows it to focus light rays, making it useful for applications like dental mirrors and reflectors in headlights.

A concave mirror causes parallel light rays to converge, focusing them to a single point. This property is utilized in applications such as telescopes and solar concentrators.

Convex mirrors are installed at road intersections to provide a wider field of view, enhancing visibility for drivers and helping to prevent collisions by allowing them to see around corners.

Images formed by plane mirrors are the same size as the object and are always upright (erect). This property is essential for everyday reflections, such as those seen in dressing mirrors.

Concave mirrors are commonly used in dental mirrors, where they provide an enlarged view of teeth when held close to the mouth, allowing dentists to see clearly in a small space.

The reflective coating applied to spherical mirrors provides the necessary reflective properties that enable them to function effectively. Without this coating, the mirror would not reflect light efficiently, thus failing to create clear images.

The first law of reflection states that the angle of incidence is equal to the angle of reflection. This law applies universally to all types of mirrors and explains how light behaves upon striking reflective surfaces.

Concave mirrors converge parallel light rays to a single point or narrow beam. This property is used in torches and headlights to produce a strong, directed beam of light, improving visibility.

• Option b) is the property of convex mirrors or diverging lenses, not concave mirrors.

• Option c) is incorrect; mirrors do not make light smaller.

• Option d) is irrelevant; light rays are not “inverted” in this context.

Spherical mirrors are created by grinding and polishing a flat piece of glass into a curved shape, followed by applying a reflective coating. This method allows for precise control over the curvature and reflective properties of the mirror.

A convex mirror has a reflecting surface that curves outward. This shape allows it to provide a wider field of view, making it ideal for use in side mirrors of vehicles and in security applications.

Convex mirrors always create images that are upright (erect) and smaller than the object, regardless of the distance from which the object is viewed. This property enhances the field of view, making convex mirrors useful for safety and security.

The primary role of a convex lens is to magnify objects. They are thicker in the middle than at the edges, allowing them to converge light rays, which results in enlarged images of objects viewed through the lens.

A flat glass surface allows parallel light rays to pass through unchanged. This property differentiates flat surfaces from curved mirrors or lenses, which alter the path of light rays.

A concave lens is thicker at the edges than at the center. This design causes light rays to diverge, making it useful for certain optical applications such as correcting nearsightedness.

Water has its maximum density at 4 °C, so in winter, the colder, lighter ice stays at the surface while the denser liquid water remains below. This prevents water bodies from freezing solid, allowing aquatic organisms to live under the ice.

Concave mirrors are used in vehicle headlights because they can focus light into a beam, allowing for greater illumination of the road ahead. This focusing effect improves visibility for drivers at night.

Concave lenses always produce images that are upright (erect) and smaller than the object, regardless of the distance. This characteristic is useful in applications like certain types of eyeglasses.

One of the dangers of using concave mirrors to focus sunlight is that they can concentrate light to a point, generating intense heat that can ignite flammable materials, posing a fire hazard if not used carefully.

Light rays passing through a convex lens converge at a focal point. This property allows convex lenses to magnify images, making them useful in various optical devices like magnifying glasses and cameras.

The second law of reflection states that the incident ray, the normal to the mirror at the point of incidence, and the reflected ray all lie in the same plane. This property ensures predictable behavior of light reflections across different mirrors.