G10 Advanced Physics: Key Concept 13 - Lenses

These flashcards cover key concepts from the lecture notes on lenses.

What are the two types of lenses described in the notes?

Converging (convex) lenses and diverging (concave) lenses.

What is the principal axis of a lens?

A line which passes through the center of a lens.

What is the definition of focal length?

The distance between the center of the lens and the principal focus.

What happens to parallel rays in a converging lens?

They are brought to a focus at the principal focus.

How are real images characterized?

Real images are inverted, can be projected onto a screen, and are formed by the convergence of light rays.

What is a virtual image?

An image that appears to meet behind the lens and cannot be projected onto a screen; it is always upright.

What is the use of a converging lens as a magnifying glass?

When the object is placed closer to the lens than the focal length, it creates a virtual, enlarged, and upright image.

How can short-sightedness be corrected?

By using a concave (diverging) lens.

What is the thin lens formula?

The equation relates the focal length (f), object distance (u), and image distance (v): 1/f = 1/u + 1/v.

What happens to an image formed when the object is placed beyond twice the focal length of a converging lens?

The image is real, diminished, and inverted.

What is the effect of a diverging lens on light rays?

It causes parallel rays of light to diverge from a point.

What does it mean when we say an image is 'enlarged'?

That the image is larger than the object from which it is formed.