Computer Science 455
Instructor: R. P. Burton
Seventh Quiz
December 8-9, 2004

Name _________________________________________	Score ____________/25


1.	What is the most significant advantage of the geometric solution 
        to the ray/sphere intersection problem relative to the algebraic 
        solution?
	a.	timely comparisons
	b.	simpler mathematics
	c.	simpler implementation
	d.	all of the above

(a)

2.	Spherical inverse mapping is simply a problem of mapping an 
        intersection point to a longitude and a latitude.
	a.	true
	b.	false
(a)


3.	Ray-plane intersection represents the ray and the plane in ______  
        ray-sphere intersection.
	a.	the same forms as
	b.	different forms from
(a)


4.	The ray-polygon intersection problem is simply the ray-plane 
        intersection problem followed by an inside-outside test.
	a.	true
	b.	false
(a)


5.	A ray is inside a box if it is inside
	a.	any one slab
	b.	any two slabs
	c.	all three slabs simultaneously
(c)


6.	The ray-sphere intersection approach can be extended from spheres 
        to all of the following except
	a.	cylinders
	b.	cones
	c.	ellipsoids
	d.	paraboloids
	e.	hyperboloids
	f.	(no exceptions here)
(f)


7.	When light strikes a surface
	a.	some of the photons are absorbed and some are reflected
        b.	all of the photons are absorbed, and new photons are emitted 
                corresponding to the "color" of the surface
(b)


8.	Fractal geometry is about ____ years old.
	a.	30
	b.	300
	c.	3000
(a)


9.	Fractal geometry is useful for producing exciting shapes and 
        artificial (but realistic) worlds, but has few if any practical 
        applications in science.
	a.	true
	b.	false
(b)


10.	Fractal geometry is suited to modeling
	a.	highly symmetrical natural patterns (such as snow flakes)
	b.	random natural patterns
	c. 	both (a) and (b)
(c)


11.	Fractals often are generated using functions in the complex plane 
        because
	a.	fractals exist only in the complex plane
	b.	fractals often involve the square roots of negative numbers
	c.	that makes it easy to separate the x and y components
(c)


12.	If random midpoint displacement is used to "fractalize" a triangle, 
        after the first step there are ___ triangles, after the second step 
        there are ___ triangles, and after the third step there are ___ 
        triangles.
	a.	2, 4, 8
	b.	3, 9, 27
	c.	4, 16, 64
(c)


13.	The von Koch snowflake exhibits
	a.	exact self-similarity
	b.	statistical self-similarity
(a)


14.	The fractal dimension of the von Koch snowflake is
	a.	1
	b.	between 1 and 2
	c.	2
	d.	between 2 and 3
	e.	3
	f.	more than 3
(b)


15.	When a fractal scene is scaled by a power law (such as take cubes 
        or cube roots of heights)
	a.	the fractal dimension changes proportionally
	b.	the fractal dimension changes as the log
	c.	the fractal dimension is unchanged
(c)


16.	The number of craters of a particular size (on the moon, for example) 
        is
	a.	independent of the size of the crater
	b.	proportional to the size of the crater
	c.	inversely proportional to the size of the crater
(c)


17.	10,000 independent surface displacements of a sphere results in
	a.	equally distributed height variations on the surface of the 
                sphere
        b.	the formation of high regions and of valleys, effectively 
                producing "continents" if water covers the sphere to a 
                certain depth.
(b)


18.	The most common noise found in nature is
	a.	white noise
	b.	1/f noise
	c.	1/f2 noise
(b)


19.	Music from which culture(s) mimics 1/f noise?
	a.	classical India
	b.	classical Europe
	c.	the "Beatles" area
	d.	American jazz
	e.	all of the above
(e)


20.	As discussed in class, the complexity of a fractal is measure by
	a.	the number of iterations needed to produce the fractal
	b.	the mathematical sophistication of the formula
	c.	the length of the shortest program that can produce 
                the fractal
(c)


21.	All fractals are deterministic (as opposed to random)
	a.	true
	b.	false
(b)


22.	Which of the following does not have a stable orbit?
	a.	sqrt(x)
	b.	sqr(x)
	c.	sin(x)
	d.	cos(x)
	e.	(all have stable orbits)
(b)


23.	General-purpose code for producing an arbitrary Julia set requires 
        approximately ____ lines of code.
	a.	20
	b.	200
	c.	2,000
	d.	20,000
(a)


24.	To produce the Mandelbrot set, ___ is added to zi2 at each iteration. 
	a.	nothing
	b.	x + iy
	c.	(x + iy) 2
(b)


25.	The relationship between the sets Julia & Mandelbrot is
	a.	1:1
	b.	many:1
	c.	1:many
	d.	many:many
(b)