LEVEL 2: Lens and Image Formation Quiz

How can you determine the focal length of a lens experimentally?

• By measuring the thickness of the lens.

• By using a distant light source like the sun and measuring the distance from the lens to the screen.

• By focusing a distant light source onto a screen and measuring the distance from the lens to the screen. (CORRECT)

• By calculating the curvature of the lens.

How does a concave lens form an image of an object placed at infinity?

• It forms a real, inverted, and magnified image at the focal point.

• It forms a virtual, upright, and highly diminished image at its focal point on the same side as the object. (CORRECT)

• It forms a real, upright, and magnified image.

• It forms a virtual, inverted, and diminished image.

How does a convex lens form an image of an object placed at infinity?

• It forms a virtual, upright, and magnified image.

• It forms a real, inverted, and highly diminished image at its focal point. (CORRECT)

• It forms a real, upright, and magnified image.

• It forms a virtual, inverted, and magnified image.

What happens to the image formed by a convex lens as the object moves closer to the lens?

• The image moves farther away from the lens, becomes larger, and eventually becomes virtual and upright when the object is within the focal length. (CORRECT)

• The image remains at the same position but becomes smaller.

• The image stays inverted and becomes smaller.

• The image disappears entirely.

What happens to the image formed by a concave lens as the object moves closer to the lens?

• The virtual image becomes inverted and larger.

• The virtual image remains upright and becomes larger but always appears smaller than the object. (CORRECT)

• The virtual image remains the same size regardless of the object's position.

• The virtual image disappears.

What is the 'optical center' of a lens?

• The point where all light rays meet.

• The point within the lens where light rays pass through without being refracted. (CORRECT)

• The point where the light rays diverge.

• The center of curvature of the lens.

How do corrective lenses for myopia (nearsightedness) work?

• They use convex lenses to converge light rays.

• They focus light on the cornea.

• They use concave lenses to diverge light rays before they enter the eye, allowing the image to focus on the retina. (CORRECT)

• They magnify the light entering the eye.

How do corrective lenses for hyperopia (farsightedness) work?

• They use concave lenses to spread light rays.

• They use convex lenses to converge light rays before they enter the eye, allowing the image to focus on the retina. (CORRECT)

• They magnify objects in the distance.

• They scatter the light entering the eye.

What are some common uses of concave lenses?

• Used in eyeglasses for correcting myopia (nearsightedness), cameras to reduce distortion, and flashlights to spread light beams. (CORRECT)

• Used in telescopes and microscopes for magnification.

• Used in magnifying glasses and projectors.

• Used in eyeglasses for correcting hyperopia (farsightedness).

What are some common uses of convex lenses?

• Used in eyeglasses for correcting myopia (nearsightedness).

• Used in magnifying glasses, eyeglasses for hyperopia (farsightedness), cameras, microscopes, and telescopes. (CORRECT)

• Used to spread light in flashlights.

• Used to reduce image distortion in cameras.