Sun: Radius = 6.9e8 m
Mass = 2e30 kg
Luminosity = 3.8e26 Watt
Why does the Sun shine? Not chemical energy/gravitational energy
but nuclear reactions! (~10 billion years)
E=mc2
mass and energy are diff
Which one of the following choices best explains why an isolated white
dwarf cannot explode as a type I supernova?
PRS 20
1) There is no companion star to heat up the white dwarf.
2) There is no exter
What is the energy released (positive) or absorbed (negative) in the
following reaction? (1amu is equivalent to 931.49 MeV)
3H
3H
4He
+
=
+
2(1n)
(3.016049amu) (3.016049amu) (4.002603amu) (1.008665amu
The hydrogen atoms in a distant star is emitting photons of light at
a wavelength of 410.17nm, however it is observed on Earth to be
shifted to 411.54 nm. The recessional speed of the distant star
alo
The noon Sun appears at different elevation from the horizon
through a year because of Earths axial tilt and _.
1) the expansion of the Universe
2) the seemingly random motion of the Sun among its nei
The look-back time of an object is directly related to its
1) size
2) composition
3) brightness
4) mass
5) distance.
PRS 1
1
The look-back time of an object is directly related to its
Correct Answer i
Why is it summer in the Southern Hemisphere when it is winter in the Northern
Hemisphere? The Southern Hemisphere is
1) closest to the sun.
2) on a path of warm winds from the North.
3) receiving the
PHYS 2022 Fall 2014
Introduction to Modern Physics
Homework 2
Due Wednesday, 17 September
Problem 1.
Derive the velocity addition formula starting from the Lorentz transform. Note that even
for motion
PHYS 2022 Spring 2013
Introduction to Modern Physics
Homework 6
Due Wednesday, 29 Oct 2014
Problem 1
According to the corresponding principle, quantum theory should give the same result
as classical p
PHYS2022 Fall 2014
Introduction to Modern Physics
Homework 4
Due Wednesday, 8 October
is the Planck constant;
is the speed of light in vacuum;
is the Boltzmann constant.
Problem 1.
In lecture, we d
PHYS 2022 Fall 2014
Introduction to Modern Physics
Homework 7
Due Wednesday, 05 Nov 2014
1) Free particle in a wave packet [40 points]
A free particle can be described as a wave packet:
+
(, ) =
wher
PHYS 2022 Fall 2014
Introduction to Modern Physics
Homework 10
Due Wednesday, 26 Nov 2014
1) The energy needed to detach the electron from a hydrogen atom is 13.6 eV, but the energy
needed to detach a
PHYS 2022 Fall 2014
Introduction to Modern Physics
Homework 1
Due Wednesday, 10 September
Problem 1.
Let
c = speed of the swimmer in still water
v = velocity of water current
L = distance between star
PHYS 2022 Fall 2014
Introduction to Modern Physics
Homework 3
Due Wednesday, 24 September
Problem 1.
(a) In lecture, we proved (
)
(
) from the space-time relation. Prove this
relation using a differe
PHYS 2022 Fall 2014
Introduction to Modern Physics
Homework 8
Due Wednesday, 12 Nov 2014
1) Show that
1
!" =
!
!
!
!
!
2 6!
is a solution of the radial wavefunction ()
1 !
2
!
+1
+
+
=0
!
!
4!
PHYS 2022 Fall 2014
Introduction to Modern Physics
Homework 5
Due Wednesday, 22 October
Problem 1.
Show that the following function of general sinusoidal wave
( x) = a sin( kx) + b cos(
PHYS 2022 Fall 2014
Introduction to Modern Physics
Homework 9
Due Wednesday, 19 Nov 2014
1) A helium atom is in an energy level with one electron occupying an s state ( = 0) and the
other an f state (
Special Techniques for
Calculating Potentials
Laplaces Equation
Recall:
Laplaces
Poissons equation:
equation:
0
V
2
1
0
The solutions of the Laplaces equation are called the harmonic functions
Laplac
Electric Fields inside
Matter
Inside a medium, unlike in vacuum, there
are a lot of charged particles, e.g.,
electrons, protons, etc.
In principle, matter is just a form of source
distribution in va
PHYS 3033/3053 Assignment 6
Due: 20 Oct 2017 at begin of lecture at 4:30 pm
Problem 1
When a neutral dielectric material is being polarized, charges move a bit, but the total charge in
the material re
_ light can be seen from stars behind a
dark nebula.
1) Blue
2) Infrared
3) Ultraviolet
4) Violet
5) Yellow
PRS 14
1
Explanation
Dust particles in a dark nebulae will scatter or even block
shorter wav
In the following diagram, which of the transitions would absorb a
photon with the shortest wavelength?
1) Transition 1
4) Transition 4
2) Transition 2
5) Transition 5
3) Transition 3
PRS 9
4
3
2
1
1st
Which of the following fusion interactions would release energy?
4He
4He
8Be
I:
+
II: 4He + 8Be 12C
III: 4He + 4He+ 4He 12C
1) I only
2) II only
Nucleus
4He
8Be
12C
3) III only
PRS11
Mass (amu)
4.0026
Vega ()s luminosity is 40 times that of the Sun.
The life expectancy of this star is _ times the lifetime of
the Sun.
1)
2)
3)
4)
5)
0.02
0.07
0.18
2
33
PRS13
1
Explanation
With L in L and M in M, we
As a white dwarf increases in mass (as a result of mass
transfer from a companion, for example), which of the
following statements is true?
1) its average density becomes smaller.
2) its on-going fusi
PRS 5
At 9 pm, Moon is seen at 45o above the
West horizon. The phase of Moon is
1) new
2) crescent
3) quarter 4) gibbous 5) full
1
Explanation
The phase of the Moon is first quarter. Answer: 3).
Firs
Suppose a planet is orbited by a number of satellites.
Which of the satellites will feel the weakest tidal forces
due to the planet?
PRS8
1) a large satellite in a close orbit; 2) a large satellite in