Phys 273 Homework #1
due Sept 7, 2010
1-7. A thin circular hoop of radius a is hung over a sharp horizontal knife edge.
Show that the hoop oscillates with an oscillation frequency
.
1-8. A marble thrown into a bowl executes oscillatory motion. Assuming th
Physics 273
Homework #11 SOLUTIONS
11.17
(a) film index n = (/0)1/2 = 2
-wave at wavelength (in film) /n=300nm is 75nm or 750
(b) From 11.16, we have the effective impedance of the -wave film is
Zeff = Zf2/Zg, where Zf=1/n = and Zg = 1. So Zeff =
2
Z ef
Physics 273 Homework #10
1. A particle of charge Q oscillates sinusoidally with frequency in the x-direction according to
x(t ) X 0 sin( t ) . We will study the resulting electromagnetic fields at a distance y
perpendicular to the motion, with y > X0 .
Q
Physics 273 Homework #10
Due: Monday, November 28, 2011
1. A particle of charge Q oscillates sinusoidally with frequency in the x-direction according to
x(t ) X 0 sin( t ) . We will study the resulting electromagnetic fields at a distance y
perpendicular
PHYSICS 273 HW #9 SOLUTIONS
9-20
Let the electric field be E0 sin kx t . Its energy density is
1
1
0 E02 sin 2 kx t with average 0 E02 . The kinetic energy density of electrons can be found from
2
4
1
1 ne2
1 ne2
1 p
nmv 2
E02 cos2 kx t with average
E02
Physics 273
Homework #7 Solutions
7.4
(a) For transverse waves on a rope, the force on longitudinal
section dx of the rope is the sum of the transverse components of
the tension on each end of section T(xdx/2)(df/dx)|xdx/2. Setting
F=ma, we have
dx f
T x
Phys 273 Homework 3 solutions
H&L 2-1. A wave can always be cast in the form f (x,t) = f (x+vt) for a wave
propagating along the x direction, and f (x,t) = f (xvt) for propagation along
the +x direction. We have f (x,t) =0.02sin[2(0.5x10t)] = 0.02sin[(x20
Phys 273 Homework 2 solutions
4-8
4-14. (a) the full-width-half-max (FWHM) of a resonance curve is /Q, and
0
given that FWHM = 0.040 from the figure, then
Q = 1/0.04 = 25
(b) the damping constant is also the FWHM of the power spectrum, so
= 0.040
(c) the
PHYSICS 273
PROBLEM SET #1 SOLUTIONS
September 13, 2011
1.7 The moment of inertia of a circular hoop of mass m and radius a rotating
about a point on its circumference is I = 2ma2. (Use the parallel axis
theorem, or integrate the mass around the hoop.)
So