Lesson 10: Concave/ Convex Lenses

Question 1

What is the purpose a lens?

Answer 1

• A lens forms an image by refracting light.

Question 2

Where are parallel rays of light bought to focus in a convex lens?

Answer 2

• In a convex lens, parallel rays of light are bought into focus at “the principal focus.”

Question 3

What is the distance from the lens to the principle focus called?

Answer 3

• The distance from the lens to the principle focus is known as: “the focal length.”

Question 4

True or False

The image produced by a convex lens is ALWAYS real.

Answer 4

• False.
• The image produced by a convex lens can either be real or virtual.
• @If the lines don’t join together on the right- side, extend them back to see if they will join on the left (if they join on the left, the image formed is virtual.)@

@= extra info/ clarification

Question 5

When you trace back lines in convex lens ray diagrams, should the lines be solid/ dotted?

Answer 5

• The lines should be dotted (when drawing a VIRTUAL image.)

Question 6

True or False

The image produced by a concave lens can either be real or virtual.

Answer 6

• False.
• The image produced by a concave lens is ALWAYS virtual.

Question 7

Where is the image formed if the image is virtual?

Answer 7

• The image will be formed behind/ before the lens.

Question 8

Where will the image be formed if the image is real?

Answer 8

• The image will be formed after/ in front of the lens.

Question 9

What is a real image?

Answer 9

• A REAL image is one that can be projected onto a screen.

Question 10

BIOLOGY LINK

What is the equation for magnification?

Answer 10

Magnification = image height/ object height.