Lenses

A convex lens is also known as a:

• Diverging lens

• Concave lens

• Converging lens

• Cylindrical lens

Answer explanation

A convex lens is called a converging lens because it bends light rays inward, causing them to converge at a focal point. In contrast, a diverging lens (concave) spreads light rays apart.

The focal length of a convex lens is:

• The distance from the lens to the object

• The distance from the lens to the image

• The distance from the lens to the point where parallel rays converge

• The diameter of the lens

Answer explanation

The focal length of a convex lens is defined as the distance from the lens to the point where parallel rays converge, making this the correct choice. The other options do not accurately describe the focal length.

What is the primary function of a convex lens?

• To diverge light rays

• To form only virtual images

• To converge light rays

• To create only diminished images

Answer explanation

The primary function of a convex lens is to converge light rays, bringing them together to a focal point. This property allows convex lenses to form real and virtual images, making them essential in various optical devices.

In which optical device is a convex lens commonly used to form a real, inverted image?

• A magnifying glass

• A camera

• A microscope eyepiece

• A projector

Answer explanation

A convex lens is used in both a magnifying glass and a projector to form real, inverted images. In a magnifying glass, it creates a larger image of an object, while in a projector, it projects images onto a screen.

What type of image is formed when a convex lens is used as a magnifying glass?

• Real and inverted

• Real and upright

• Virtual and inverted

• Virtual and upright

Answer explanation

A convex lens used as a magnifying glass produces a virtual and upright image when the object is within the focal length. The correct answer is 'Virtual and upright', not 'Real and inverted'.