WAVES AND OPTICS

Question 1

What are the three key rays passing into the lens?

Answer 1

1. Ray comes in parallel to axis and exits AT the focal point
2. Ray comes through the focal point and exits parallel to the axis
3. Neither deflected nor displaced (passes through centre of lens)

Question 2

What is a virtual image?

Answer 2

When an image is in front of the lens, the image distance (di) then becomes negative

Question 3

Do we need to convert the cm in the lens equation to m?

Answer 3

NOOO! only in the power equation

Question 4

What is the far point?

Answer 4

the farthest point that the person can see things clearly

Question 5

Where is the observer?

Answer 5

Behind the lens

Question 6

What does a negative magnification mean?

Answer 6

It is an inverted image (upside down)

Question 7

What happens to the image when an object gets closer?

Answer 7

It will be farther away from the image

Question 8

What happens if the object is inside the focal point?

Answer 8

virtual image

Question 9

What does a positive magnification tell us?

Answer 9

That the image will be upright (not inverted )

Question 10

How does a magnifying glass work?

Answer 10

If an observer looks through converging lens and an object is placed closer to the lens than the focal point, then the person will see a VIRTUAL image on the other side of the lens that looks MUCH larger than the object.