Understanding Concave Lenses: Formation and Types of Images

This video tutorial explains the properties and functions of concave lenses, including how they refract light to form virtual images. It covers the basic principles of lenses, the concept of focal length, and the power of lenses. The tutorial also provides a step-by-step guide on drawing ray diagrams for concave lenses and compares the characteristics of concave and convex lenses.

What happens to light when it crosses the boundary between two different media?

• It refracts, changing direction and speed.

• It accelerates without changing direction.

• It continues in the same direction at a slower speed.

• It stops completely.

How does a concave lens affect parallel light rays?

• It absorbs them completely.

• It converges them to a point.

• It diverges them, spreading out.

• It reflects them back.

What is the relationship between the focal length and the power of a lens?

• They are equal.

• They are unrelated.

• They are inversely proportional.

• They are directly proportional.

In a ray diagram for a concave lens, what is the direction of the first light ray after refraction?

• It moves downward.

• It moves towards the principal axis.

• It moves away from the principal axis.

• It remains parallel to the principal axis.

What type of image is always formed by a concave lens?

• Virtual, inverted, and larger.

• Real, upright, and the same size.

• Virtual, upright, and smaller.

• Real, inverted, and larger.

How does a convex lens differ from a concave lens in terms of structure?

• A convex lens is thinner in the center.

• A concave lens is thicker in the center.

• A convex lens is thicker in the center.

• Both lenses have the same thickness throughout.

Which of the following is true about the images formed by convex lenses?

• They are always smaller than the object.

• They are always the same size as the object.

• They are always virtual and upright.

• They can be real or virtual, inverted or upright.