Exam (elaborations)
PHY1506 EXAM PACK 2025 {DETAILED QUESTIONS AND ANSWERS }
- Course
- Electromagnetism and Heat
- Institution
- University Of South Africa
PHY1506 EXAM PACK 2025 {DETAILED QUESTIONS AND ANSWERS }
[Show more]
Content preview
lOMoAR cPSD| 49074884Downloaded by Vincent master ()
, lOMoAR cPSD| 49074884
Chapter 1
Macroscopic description of matter
1.1 State of the matter
There are three common states of the matter
1. Solid
- Incompressible
- particles-like atoms connected by molecular
bonds - etc.
2. Liquid:
- Formed by loosely-bound together molecules.
- Nearly incompressible.
- Flows and deforms to fit the shape of the
container.
- etc.
3. Gas:
- Highly compressible - Large space between
molecules - etc.
1
Downloaded by Vincent master ()
, lOMoAR cPSD| 49074884
2 CHAPTER 1. MACROSCOPIC DESCRIPTION OF MATTER
1.2 State variables
State variables are parameters used to
characterize or describe a macroscopic system. A
system is said to be in thermal equilibrium if the
state variables are constant, i.e., not changing.
1.3 Atoms and moles
The mass of a system is related to its number of
atoms or molecules (we represent this number by
N). The number of atoms or molecules per unit
of volume is called number density, defined by
the ratio N/V , where V is the volume of the
system. Notice that the number density is the
same whether one considers the whole system or
a portion of it. This means that the value of the
ratio N/V is constant.
1.3.1Atomic mass and atomic mass number
(a) Atomic mass Since the atom is composed of
protons and neutrons, the atomic mass number
represents the sum of protons and neutron of
the atom, and is given by
A = Nn + Np,
where
A: atomic mass number
Nn: number of neutrons
Np: number of protons
Downloaded by Vincent master ()
, lOMoAR cPSD| 49074884
Example:
1
H: A = 1
4
He: A = 4
12
C: A = 12.
(b) Atomic mass (unit “u”)
The atomic mass is obtained by considering
the mass of Carbon-12 (12C) to be exactly 12u.
This means that m(12C) = 12u. For example, an
experimental study of the hydrogen atom
showed that the ration m(1H)/m(12C) =
1.0078/12. This means that the atomic mass of
hydrogen is 1.0078u. In this study guide, we
will loosely define the atomic mass of a
chemical element as its mass number with the
unit “u”. For example, the atomic mass of
Helium will be m(4He) = 4u, m(20Ne) = 20u,
etc.
Downloaded by Vincent master ()
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through EFT, credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying this summary from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller MasterVincent. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy this summary for R52,04. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
68175 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy summaries for 15 years now