homework for Monday

A few things to do for Monday:

1.  Review the concept of critical angle and the related formula.

2.  Calculate the critical angle of diamond (n = 2.417).

3.  If a substance has a critical angle of 60 degrees, what is its index of refraction?

4.  What is the critical angle of air (n = 1.0028).  One of the classes did this already.

5.  (Review problem.)  A 475 nm light ray hits a tank of water (n = 1.33) at an angle of 30 degrees with respect to the normal line.  Find the angle of refraction, speed and wavelength inside the water.

6.  Prep for the next formal lab.  To do this, research the following:

a.  focal length.  What is the definition?

b.  Our next lab will investigate the question:  what is the relationship between the location of an object (how close it is to a lens) and whether or not an image forms, and the nature of the image that forms (bigger or smaller image, where it forms, etc.).  Decide on a type of protocol to investigate these questions.

More Snell's Law fun!

(Trig practice)

1.  Consider a triangle with sides 20,21, and 29.  Find all the angles in the triangle.

2.  Choose any other Pythagorean triple and find the angles in the triangle:

http://en.wikipedia.org/wiki/Pythagorean_triple

(Snell's Law)

3.  A 450 nm blue light ray hits a piece of Plexiglas (n = 1.6) at an angle of 55 degrees with respect to a normal line.  Find the following:

a.  picture that represents what happens

b.  angle inside Plexiglas

c.  wavelength inside Plexiglas

d.  speed of light inside Plexiglas

4.  Light hits a piece of unknown material, such that the light refracts from 60 degrees to 35 degrees.  If the light enters from air, what is the index of refraction of the material?

5. Review all of the relevant formulas discussed so far to make sure you understand each one.  Include the new ones from class today.

Homework for after test

Try these, even if your trig is poor or nonexistent.

Snell's Law images from today's class

Sample Doppler problem

Consider a siren that has a 1200 Hz tone attached to an ambulance traveling at 35 m/s.  Find the following frequencies:

a.  what you hear when the ambulance approaches you
b.  what you hear when the ambulance travels away from
c.  what you hear if you were in a car traveling toward the ambulance, you moving at 15 m/s

Interesting and cool - not physics related, but math and politics related

http://www-personal.umich.edu/~mejn/election/2012/

Test Friday - practice problems for recent stuff

1.  Doppler effect.  A police car approaches you.  According to the siren's manufacturer, the frequency is 1000 Hz.  How would the frequency change if you were located:
a.  behind the car as it passed you
b.  in front of the car as it approached you
c.  in the car
d.  running toward the car, if it were at rest
e.  running away from the car, if it were at rest

2.  What does the red shift of distant galaxies suggest?

3.  What do red shift and blue shift mean?

4.  Explain the Doppler effect.

5.  Consider a 320 Hz note (E, approximately).  What is the frequency of:
a.  the next E (one octave above)
b.  the E one octave below
c.  an E that is 3 octaves above
d.  an F, one semi-tone above
e.  a G, three semi-tones above

Don't forget to review strings, organ pipes and all other wave phenomena.