Unit 5 Lenses

What would you use a hands lens or magnifying glass for?

• to see objects that are very small

• to make objects appear smaller

• to turn objects upside down

Answer explanation

A hands lens or magnifying glass is used to see objects that are very small by enlarging their appearance, making it easier to observe details that are not visible to the naked eye.

A convex lens is able to project an image onto a screen because...

• the lens bends light inward and creates a virtual image

• A convex lens reflects light rays to form a distorted image on a screen.

• A convex lens absorbs light rays to create darkness on a screen.

• the lens bends light inward and creates a real image.

Answer explanation

A convex lens bends light rays inward, allowing them to converge and form a real image on a screen. The correct choice highlights this process, while the other options incorrectly describe the lens's function.

The lens shown causes the light rays entering the lens to spread out. Which of the following statements describe an application BEST suited for the lens shown in the picture.

• Magnifying glasses for reading

• Projector lenses for displaying images

• Camera lenses for capturing distant scenes

• A flashlight that will allow light exiting the flashlight to reach a larger area.

Answer explanation

The lens spreads light rays, making it ideal for a flashlight to illuminate a larger area. Other options focus light rather than spreading it, making them less suitable for this lens's function.

Which of the following best describes the path of light rays passing through a glass prism?

• Light rays are absorbed by the prism material.

• Light rays pass straight through without bending.

• White light passes through and splits into the different wavelengths of visible light. Red is on top because it has the longest wavelength.

• Light rays reflect off the surface of the prism.

Answer explanation

The correct choice explains that white light enters the prism and is refracted, splitting into different wavelengths. Red light, having the longest wavelength, appears at the top, demonstrating the dispersion of light.

Tags

NGSS.MS-PS4-2

Choose all the describe a convex lens.

• Light rays converge.

• Light rays diverge.

• Light rays come together.

• Light rays spread out.

Answer explanation

A convex lens causes light rays to converge, meaning they come together at a focal point. Therefore, the correct descriptions are 'Light rays converge' and 'Light rays come together'. The other options describe diverging lenses.

Choose all that describe a concave lens.

• Light rays diverge.

• Light rays converge.

• Light rays come together.

• Light rays spread apart.

Answer explanation

A concave lens causes light rays to diverge, meaning they spread apart. This is why the correct choices are 'Light rays diverge' and 'Light rays spread apart.' The other options describe the behavior of convex lenses.

What type of lens is shown?

• Concave lens-it spreads the light from the focal point. (diverge)

• Convex lens-it focuses the light a the focal point (converge)

Answer explanation

The lens shown is a concave lens, which diverges light rays. It spreads light from the focal point, making it useful for correcting nearsightedness. In contrast, a convex lens converges light at the focal point.

What type of lens is shown?

• Concave lens-it spreads the light from the focal point. (diverge)

• Convex lens-it focuses the light a the focal point (converge)

Answer explanation

A convex lens converges light rays to a focal point, making it the correct choice. In contrast, a concave lens diverges light rays, spreading them out.

Why are convex lenses best for magnifying glasses?

• They focus the light to make the object appear larger.

• They spread the light to make the object appear larger.

• They focus the light to make the object appear smaller.

Answer explanation

Convex lenses bend and focus light rays to converge at a point, creating a magnified image of the object. This focusing effect makes the object appear larger, which is why they are ideal for magnifying glasses.

How do light and lenses work together?

• Light travels faster through lenses than in air.

• Light and lenses work together by bending light rays.

• Lenses absorb light without altering its path.

• Lenses create light by generating energy from darkness.

Answer explanation

Light and lenses work together by bending light rays. Lenses change the direction of light as it passes through them, allowing us to focus or disperse light, which is essential in devices like glasses and cameras.

Tags

NGSS.MS-PS4-2