Physics & Laser BAS 111 Lecture 1: Measurements

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Questions and Answers

What does a scientific measurement require?

The tools necessary for the measurement.

The definition of the physical quantity and units. (correct)

The result of previous measurements.

Only a definition of the physical quantity.

In the Système International (SI) of units, what are derived units?

Units expressed in terms of one or more base units. (correct)

Units that cannot be expressed in terms of base units.

Units that require measurement tools to define.

Units that are only applicable in specific scientific fields.

Which of the following best describes mass?

The gravitational force acting on an object.

The total distance an object travels.

The time taken for an event to occur.

The measure of matter contained in an object. (correct)

Which of the following quantities is considered a basic quantity?

Length Signup and view all the answers

What is the main focus of physics as studied in this course?

The interactions of basic components of the universe. Signup and view all the answers

What is the SI unit for measuring time?

Second Signup and view all the answers

Which component of a pendulum clock is responsible for keeping the pendulum swinging?

Mass at the end of the chain Signup and view all the answers

Which type of stopwatch is known for measuring time with greater accuracy?

Digital stopwatch Signup and view all the answers

What describes the time for one complete oscillation of a pendulum?

Period Signup and view all the answers

What primarily keeps quartz crystals vibrating in most watches?

Electric battery Signup and view all the answers

What are the SI units for density?

kg/m³ Signup and view all the answers

Which of the following equations correctly defines pressure?

Pressure = Force ÷ Area Signup and view all the answers

What is the derived unit for work?

N·m Signup and view all the answers

Which prefix corresponds to a factor of $10^{-6}$?

micro Signup and view all the answers

How is speed defined in terms of its derived units?

m/s Signup and view all the answers

What is the SI unit for force?

Newton Signup and view all the answers

Which of the following is NOT considered a base quantity?

Volume Signup and view all the answers

What does the prefix 'giga-' represent?

10⁹ Signup and view all the answers

Study Notes

Course Information

Course Title: Physics & Laser
Course Code: BAS 111
Department: Physics
Lecturer: Dr. Yasser Abdou
Email: [email protected]

Lecture 1: Measurements

What is Physics?

Physics is the study of the basic components of the universe and their interactions.
Theories of physics must be verified by experimental measurements.

Measurement

A scientific measurement requires the definition of the physical quantity and its units.
The value of a physical quantity is a number multiplied by a unit.
The precision of a measurement result depends on the procedures used to make the measurement.

Basic Measurements

Length: Measuring the distance between two points.
Time: Measuring how long an event takes.
Mass: Measuring the amount of matter.

The Système International (SI) of Units

The SI, or metric system, is the internationally accepted system of units for scientific measurements.
The SI consists of base units and derived units.
- Base units are fundamental units for measuring physical quantities.
- Derived units are combinations of base units.

Physical Quantities

Physical quantities are classified into base quantities and derived quantities.
- Base quantities are the foundational quantities upon which other quantities are based.
- Derived quantities are obtained by combining base quantities through relationships.
Example: Speed is a derived quantity, calculated from distance and time.

SI Base Units

Length: Meter (m)
Time: Second (s)
Mass: Kilogram (kg)
Amount of substance: Mole (mol)
Electric current: Ampere (A)
Thermodynamic temperature: Kelvin (K)
Luminous intensity: Candela (cd)

SI Derived Quantities

Area: m²
Volume: m³
Density: kg/m³
Speed or Velocity: m/s
Acceleration: m/s²
Force: kg⋅m/s² (Newton)
Pressure: N/m² (Pascal)
Work: N⋅m (Joule)
Power: J/s (Watt)

Prefixes

Prefixes are used to denote very large or very small quantities.
Example: kilo (1000), milli (0.001)

Alternative Writing Method (Standard Form)

Expressing very large or very small numbers as N × 10ⁿ, where 1 ≤ N < 10 and n is an integer.

Key Concepts

A physical quantity is a quantity that can be measured, consisting of both numerical magnitude and unit.
Physical quantities are classified into base quantities and derived quantities.
There are seven base quantities (length, mass, time, electric current, thermodynamic temperature, amount of substance, luminous intensity).

Questions (from the slides)

Questions regarding base quantities, convenient ways of writing quantities, and converting units were presented. These are not the answers but rather questions for the student.

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Description

Explore the basics of measurements in physics with a focus on the scientific definitions and units. Understand the importance of precision and the role of the Système International (SI) of Units. This quiz will help reinforce your understanding of fundamental physical quantities such as length, time, and mass.