Home

WarmUp

What is Physics Good For?

Warming up on... Lenses

This assignment is due before 9 AM, Friday, November 2^nd, 2007.

Please type your last name and first initial (e.g., Rader, A):

Please type a nickname: (in case your answer gets used in class).

The following questions refer to the material you were to read in preparation to the lesson. Please write a three or four sentence response to each of the questions.

You may change your mind as often as you wish. When you are satisfied with your responses, click the SUBMIT HOMEWORK button at the bottom of this page.

WarmUp questions are worth 4 points.

1.

Images formed by lenses can be real or virtual. What does it mean for an image to be virtual? Can such an image be seen?

2.

The lens at the front of your eye must produce a sharp image on your retina, at the back of your eyeball. If your vision is good, it can do this whether the object is 1 foot or 100 yards away. Estimate the range of focal lengths that a "good" eye can adopt. (Hint: your eye is a sphere with a diameter of about an inch.)

3.

The focal length of a flat piece of glass is

Undefined

Zero

1 meter

Infinite

It depends on the size of the piece

4.

If two lenses are placed in a row, so that light from an object passes through both of them, the focal length of the pair of lenses is

Undefined

the sum of the focal lengths of the two lenses

the product of the focal lengths of the two lenses

the difference of the focal lengths of the two lenses

dependent on the distance between the two lenses.

Below is a space for your thoughts, including general comments about today's assignment. What was hard or confusing (or cool)? What would you like to spend extra time on in class? Do you see how this subject fits in with the others we have discussed?

You may change your mind as often as you wish. When you are satisfied with your responses click the SUBMIT button.

This site is made possible by funding from the National Science Foundation (DUE-9981111).

This assignment is due before 9 AM, Friday, November 2nd, 2007.

1.

2.

3.

4.

This assignment is due before 9 AM, Friday, November 2^nd, 2007.