Applied Physics Lecture

1. Engr. Muhammad Zain Jan
Applied Physics
NS-111

2. Course Outline
Topics include an introduction to the basics of Applied Physics,
including the Electric field, Understanding the conservation of
charge, Ring of Charge & Disk of Charge, Flux of a vector, and
electric field using Gauss’s Law, Halls effect and magnetic force
on a current, The Biot-Savart Law, working of Solenoid and
Toroid, Faraday’s Law of Induction, Lenz’s Law, Motional EMF,
and relevant literature.
Recommended Books
Textbook: Fundamentals of Physics (Extended) 10th
Edition, Resnick and Walker
Reference Book: “Physics for Computer Science Students,”
Springer Verlag, 1998
Online Material: Accordingly, for the updated course
content and literature.

3. The Goals of the course are to:
• Comprehend the fundamental laws of physics
relevant to Computer Science students.
• Apply knowledge of basic physical laws to solve
applied problems.
• Analyze different physical problems using the laws of
physics from different areas.
Course Goals

4. House Rules

5. Assessment and Weights
Sessional Test 04
Quiz 04
Assignments 04
Attendance 04
End Term Report 04
Mid Semester Exam 30
End Semester Exam 50
Presentations are expected at the end of the term on different projects related to Web Content Writing which
would enhance each student’s oral and written skills.

6. 1st Term Mid Term Exams 2nd Term 2nd Term End Term Exam
1 Quiz 1 Quiz Presentation
1 Assignment
1 Sessional Test
30 Marks 1 Assignment
1 Sessional Test
End Term Report 50 Marks

7. Why Applied Physics in Computer Science?
Physics and Computer Science are two complementary
fields. Physics provides an analytic problem-solving outlook
and a basic understanding of nature. At the same time,
computer science enhances the ability to make practical
and marketable applications, in addition to having its
theoretical interest.
The Joint Major in Physics and Computer Science
combines these two areas of study to give you a solid
grounding in both while providing you with a unique
scientific perspective. For example, your computer science
knowledge can help solve complex problems in the realm
of physics.

8. Importance of Physics
in CS
There are many important impacts of physics on
computer science.
• Physics of Spinning Disks
• Speed of Light
• Quantum Physics

9. Pure Physics versus Applied Physics
Physics studies matter, its motion through space and time, and
how it reacts with heat, light, electricity, and sound. Physics also
strives to study and understand the related forces, such as energy
and force.
Applied physics deals with practical physics, i.e., the study of
things for practical application. Applied physics is a class of
physics intended for a particular technological or practical use.
Hence, the main difference between Physics and Applied Physics
is that Physics is a field of study of the natural phenomenon. In
contrast, applied physics is a field of study under physics.

10. Pure Physics Applied Physics
Description
Physics studies matter, force,
and energy, as well as their
interaction with the world.
Applied physics is physics which
is intended for a particular
technological or practical use.
Type of Natural Science Physics
About
All about nature, natural
phenomenon, and human
understanding of all
relationships
Using physics in real world
application to develop new
technologies and to improve
current technologies
Characteristics
• Understanding the laws of
physics
• Understanding how the
world works
• The study of the universe,
what make the universe and
how the universe operates.
• Real-world applications
• Developing new technology
• Intended for practical use of
physics
• Closely related to
engineering and CS

11. Introduction to Basic Concepts

12. Measurement
Physics is based on the measurement of physical quantities.
Certain physical quantities have been chosen as base quantities
(such as length, time, and mass); each has been defined in terms
of a standard and given a unit of measure (such as meter, second,
and kilogram). Other physical quantities are defined in terms of
the base quantities and their standards and units
A measurement is an assortment of quantitative or numerical data
describing an object’s property or event.
The study of measurement is called metrology.
The National Institute of Standards and Technology (NIST) in the
US has primary responsibility for the development of standards of
measurement

13. Base Quantities
There are so many physical quantities that it is a problem to organize them. Fortunately, they are not all
independent; for example, speed is the length ratio to time. Thus, we pick out—by international
agreement—a small number of physical quantities, such as length and time, and assign standards to
them alone. We then define all other physical quantities in terms of these base quantities and their
standards (called base standards).
Many SI-derived units are defined in terms of these base units. For example, the SI unit for power called
the watt (W)
1 W= 1 kg . m2/s3

15. Derived Quantity
• A derived quantity is a physical quantity that is not a base quantity. These are the quantities derived
from the base quantities by multiplying and/or dividing them.
• No derived quantity is obtained by adding or subtracting two base quantities.
• For example, speed is defined as the rate of change of distance; mathematically, we write this as
Speed = Distance/Time. Both distance and time are base quantities, whereas speed is a derived
quantity as it is derived from distance and time through division.

17. Supplementary Units
The supplementary unit is referred to as a dimensionless unit that is employed with the fundamental
units to create the derived units. The supplementary units are utilized in two major geometric variables:
phase angle and solid angle.
Phase Angle --- Radian --- rad
Solid Angle --- Steradian ---- sr

18. Changing Units
We often need to change the units in which a physical quantity is expressed.
The are two Possibilities of doing so,
i. Conversion of a unit into multiple or submultiple of the same unit.
1 m = 100 cm , 1ns = 10-9 s , 1km = 1000 m
ii. Conversion from one unit to another unit of the same physical quantity.
Time: 1 min = 60 sec , 1 hr = 60 min, 1 hr = 3600 sec
Length: 1 foot = 12 inches, 1 mile = 1609 m
Volume: 1 gallon = 231 (inches)3

19. Changing Units
The conversion can be done by a method called “Chain-Link Conversion.”
In this method, we multiply the original measurement by a conversion factor (a ratio of units equal to
unity). For example, because 1 min and 60 s are identical time intervals, we have.
Thus, the ratios (1 min)/(60 s) and (60 s)/(1 min) can be used as conversion factors. This is not the same
as writing
1
60
= 1 𝑜𝑟 60; each number and its unit must be treated together.

20. Significant Figures and Decimal Places
The significant figures of a given number are those significant or important digits that convey the
meaning according to its accuracy. For example, 6.658 has four significant digits. These substantial
figures provide precision to the numbers. They are also termed significant digits.
The position of a digit to the right of a decimal point is defined as Decimal Place.
How many significant figures is 246.32?
How many significant figures is 8765?
How many significant figures is 0.678?
How many significant figures is 0.00082?
Don’t confuse significant figures with decimal places. Consider the lengths 35.6 mm, 3.56 m, and
0.00356 m. They all have three significant figures but have one, two, and five decimal places,
respectively.

21. 1. Determine the volume of 16 gallons in cm3
2. Convert 55 miles/hr to m/s
3. Spacing in a book was generally done in units of points and picas:
12 points = 1 pica, and 6 picas = 1 inch.
If a figure was misplaced in the page proofs by 0.80 cm, what was the
misplacement in
(a) picas
(b) points?
PROBLEMS

22. Electric Field
The electric field E is a vector quantity that exists at every point in space. The electric field at a location
indicates the force that would act on a unit positive test charge if placed at that location.
In computers, an electric field is used to turn electric current on or off, corresponding to logic 1 and 0,
the basis of binary code.
North Carolina State University researchers have discovered a technique for controlling light with
electric fields.
With this discovery, a light may be controlled to be strong or weak, spread or focused, pointing in one
direction or another by an electric field.

23. Questions & answers

24. Supplementary Data