Physics education research, electronic materials, and the musings of Christopher Moore, Ph.D.

7.   A wave is traveling through a 35.0-meter-long cable strung with a tension of 35,000N. The mass of this length of cable is 10.2 kg. What is the speed of a wave that is traveling in the cable?

8.  How long must a pendulum in your grandfather clock be in order to have a frequency of one cycle in 2 seconds?

9.  What is the only thing that affects the period of a pendulum here on Earth?

10.  You are lost in the wilderness, carrying only a piece of aluminum foil. Thanks to diligent study in your biology class, you remember which mushrooms are poisonous, and you are able to pick others that won't kill you. Your talents in basket weaving also pay off magnificently, as you create a basket and devise a plan to line it with aluminum foil, making a solar cooker.  Mmmm, roast mushrooms! The basket is a section of a sphere with radius 21.0 cm. How far from the bottom of the basket should you place the mushrooms to cook them most efficiently using the Sun's rays?  Is the sphere shaped basket the best?

11.  A mirror creates an image of magnification -1/3. (a) Is the image upright or inverted?   (b) If the object is 7.80 cm tall, what is the height of the image?

12.  A mirror produces an inverted image 2.80 cm tall when a 5.60 cm tall object is 25.0 cm away from it. (a) What is the image distance? State your answer with the correct sign. (b) What is the focal length of the mirror? State your answer with the correct sign.

13 Light of wavelength X travels more slowly in glass than light of wavelength Y. (a) Which light refracts (bends) more as it travels from air to glass?

14.  As light travels between media with different indices of refraction, which of the following wave properties changes: speed, frequency, wavelength?

15.  A beam of light travels from a medium with an index of refraction of 1.25 to a medium with an index of refraction of 1.46. If the incoming beam makes an angle of 14.0° with the normal, at what angle from the normal will it refract?

Bonus:  A beam of light travels through 4 mediums on its journey to an diamond on the bottom of a fish tank.  The wave has an original angle of 32* from the normal as it crosses the first interface.  What is the angle coming out the last interface?
Air n=1, glass n=1.51, water n=1.33, diamond n=2.42