# Quantum mechanics

Quantum Mechanics Chapter Two Dr Azeez Barzinjy
42
Classical interpretation: interference pattern appears due to interference
between waves passing through the two different slits.
Quantum view: a photon might be described as wavelike while passing
in the slits but becomes particle when it interacts with the
screen (duality)
Problem Set (2)
Q1 (a) does the de Broglie wavelength apply only to “elementary
particles” such as an electron or neutron or does it apply as well to
compound systems of matter having internal structure? Give examples.
(b) If in the de Broglie formula, we will let m→∞, do we get classical
result for microscopic particles?
Q2 Discuss similarities and differences between a matter wave and an
electromagnetic wave.
Q3 Show that for a free particle the uncertainty relation can also be written
as ∆λ∆x ≥
λ
2

where ∆x is the uncertainty in location of the wave and ∆λ
the simultaneous uncertainty in wavelength.
Q4 If ∆λ
λ
= 10−7
for a photon, what is the simultaneous value of ∆x for:
(a) λ = 5 × 10−4A
o
(𝑋 − ray)?
(b) λ = 5 A
o
(𝑋 − ray)?
(c) λ = 5000 A
o
(yellow light)?
Screen
Light
waves
Interference pattern demonstrates wave properties.
Quantum Mechanics Chapter Two Dr Azeez Barzinjy
43
Q5 A microscope using photon is employed to locate an electron in an
atom to within a distance of 0.2 A
o
.What is the uncertainty in the velocity
of the electron located in this way?
Q6 A laser beam λ = 632.8 nm is incident on two slits 0.2mm apart. How
far apart are the bright interference fringes on screen 5m away from the
double-slits?
Q7 You can read these words because particles of light, photons, have
bounced off the screen or paper and reached your eyes. Why you cannot
do so, similarly, bounce a photon off an electron and detect that photon
with an instrument?
Q8 Discuss how Heisenberg’s uncertainty principle can explain a type of
Note: Alpha particles are two protons and two neutrons emitted by some
heavy nuclei, such as uranium 238.
Q9 A localized particle in Quantum Mechanics is described by a wave
packet in position space, regardless of its energy. However, from the point
of view of General Relativity, if the particle’s energy density exceeds a
certain threshold, it should be a black hole. Explain this statement
carefully.
Practice Tests
P1 An attempt carefully observes the electron orbit leads to an
uncontrollable perturbation of the observe system.
Sol. 1:
𝜆 << 𝑎 observed from x-ray
a: is a radius of 1st Bohr orbit ~53 pm
For electron ∆p ~

λ

λ

a
,

a
=
6.62 × 10−34
2π(53 × 10−12)
≈ 2 × 10−24kg.
m
s
𝜆
a

Basic features
• Free title page and bibliography
• Unlimited revisions
• Plagiarism-free guarantee
• Money-back guarantee
On-demand options
• Writer’s samples
• Part-by-part delivery
• Overnight delivery
• Copies of used sources
Paper format
• 275 words per page
• 12 pt Arial/Times New Roman
• Double line spacing
• Any citation style (APA, MLA, Chicago/Turabian, Harvard)

# Our guarantees

We value our customers and so we ensure that what we do is 100% original..
At Custom Writing, we believe in exemplary services that are fully geared toward customer satisfaction. That is why we don’t shy away from giving you the following guarantees;

### Money-back guarantee

Trusting us with your work is the best decision you have made, our pleasure lies in seeing you satisfied at 100%. If in the rear chance it happens that you are not satisfied, then know that we will equally not be satisfied. But worry not, our 30 days- Money back guarantee is all you need and that is what we promise you..

### Zero-plagiarism guarantee

We utilize profoundly equipped and gifted writers who produce unique papers liberated from any form of plagiarism. To guarantee this, we run all papers finished by our scholars through a Plagiarism checker to ensure uniqueness and originality. In any case, on the off chance that you have vulnerabilities about the originality or falsification of any paper we have finished and conveyed to you, please get in touch with us straight away. We will quickly investigate, and if the paper is seen as counterfeited, we will take suitable actions including but not limited to, revising the paper for free and in extreme cases we will activate the money back guarantee.

### Free-revision policy

We have an obligation deliver great and specially composed assignments. Our revision strategy endeavors to ensure total client satisfaction, comfort, and a genuine feelings of serenity. We make minor updates and corrections to the underlying request as part of our continuous assistance. However, revisions should just incorporate changes and alterations that were not effectively met, in the underlying request and that are inside the rules as per the current request structure..

Our client's Data is an Integral part of our business but clearly, we are not in the business of offering our clients' very own data to others. We realize that you care how your online data is utilized and shared, we equally value your trust that we will do so cautiously and sensibly. We Promise to ensure the security of your own data during transmission by utilizing encryption conventions and programming. Likewise assist us with securing your information by not sharing your passwords and usernames.

### Fair-cooperation guarantee

In submitting a request with us, you consent to the services we give. We will strive to take the necessary steps to convey a far reaching paper according to your prerequisites. Equally we depend on your cooperation to guarantee that we convey on this order.

## Calculate the price of your order

550 words
We'll send you the first draft for approval by September 11, 2018 at 10:52 AM
Total price:
\$26
The price is based on these factors: