Which device could produce a tiny spot of light on the screen?

Which device could produce a tiny spot of light on the screen?

• A. Concave lens
• B. Convex lens
• C. Flat mirror
• D. Opaque card

Answer: (B)

A convex lens is the correct choice for producing a tiny spot of light on the screen. When light rays pass through a convex lens, the lens causes the rays to converge to a point. This is due to the curvature of the lens, which causes parallel rays of light to focus at a specific point known as the focal point. If the light source is small and positioned at or near the focal point of the lens, it will project a concentrated spot of light on the screen, allowing for a sharp and bright image. In contrast, a concave lens diverges light rays, spreading them out instead of focusing them. This results in a wider area of light distribution, not a concentrated spot. A flat mirror reflects light but does not converge or focus the light into a small point, thus failing to generate a tiny spot of light. An opaque card blocks light entirely, preventing any light from being produced or focused, and would not create a spot on the screen at all.

A convex lens is the correct choice for producing a tiny spot of light on the screen. When light rays pass through a convex lens, the lens causes the rays to converge to a point. This is due to the curvature of the lens, which causes parallel rays of light to focus at a specific point known as the focal point. If the light source is small and positioned at or near the focal point of the lens, it will project a concentrated spot of light on the screen, allowing for a sharp and bright image.

In contrast, a concave lens diverges light rays, spreading them out instead of focusing them. This results in a wider area of light distribution, not a concentrated spot. A flat mirror reflects light but does not converge or focus the light into a small point, thus failing to generate a tiny spot of light. An opaque card blocks light entirely, preventing any light from being produced or focused, and would not create a spot on the screen at all.