Notes, summaries, assignments, exams, and exercises for Physics for Other courses

Electric Charge

Electric charge exists in two types: negative (like the electron) and positive (like the proton). It is measured in coulombs (C).

Coulomb's Law

Charges repel if they have the same sign, or attract if they have opposite signs. The force increases with the product of the charges and decreases proportionally to the square of the distance separating them.

Electric Field

A vector field where the direction is defined by the path a positive charge would follow. Its modulus is the ratio of the electric force to the value of the test charge.

Superposition Principle

The vector sum of individual forces and fields acting on any charge in the proximity of others.

Field Lines

The path followed by a positive charge located in a field. These open lines...

Methods of Electrification

• Electrification by Friction

  This process involves the transfer of electrons, where one material loses electrons and another gains them.

• Electrification by Induction

  In this method, no electron transfer occurs between objects. Instead, there is a redistribution of existing electric charges within the body.

• Electrification by Contact

  When a negatively charged object touches a neutral body, negative charge is transferred from the charged body to the neutral one.

Lightning: Natural Electrical Discharges

Clouds become electrically charged by friction with air due to their motion. The top of a cloud often becomes positively charged, while the bottom accumulates negative charges. This charge separation, along with the Earth's surface,...

Wave Motion

Wave motion refers to the transmission of a disturbance from one point to another without the net transport of matter.

Wave Classification

Based on Direction of Propagation

• One-dimensional waves: Propagate in a single direction.
• Two-dimensional waves: Propagate in two directions.
• Three-dimensional waves: Propagate in three directions.

Based on Medium of Propagation

• Mechanical waves: Require a material medium for propagation. Their speed depends on the characteristics of the medium.
• Electromagnetic waves: Do not require a material medium and can propagate in a vacuum (e.g., visible light).

Based on Direction of Disturbance

• Transverse waves: The direction of propagation is perpendicular to the direction of the disturbance.
• Longitudinal waves:

States of Matter and the Kinetic Molecular Theory

• Brownian motion: The random movement of microscopic particles suspended in a liquid or gas.
• Kinetic Molecular Theory: The idea that all substances are composed of entities that are in constant, random motion.
• Kinetic energy: Energy possessed by moving objects.
• Temperature: A measure of the average kinetic energy of the entities of a substance.

The Atmosphere and Its Components

• Greenhouse effect: A natural process whereby gases and clouds absorb infrared radiation emitted from Earth’s surface and radiate it, heating the atmosphere and Earth’s surface.
• Carbon sequestration: The process of removing carbon dioxide and other forms of carbon from the atmosphere, and then storing it.

Air Quality

• Photochemical

Amplification of Light in Lasers

All lasers contain a substance that can increase the intensity of light passing through it.

The Active Medium

This substance is called the active medium and may be a solid, liquid, or gas. The mechanism by which the active medium increases the intensity will be explained later. For the moment, assume that light amplification is possible.

For example, in a YAG laser (Nd:YAG), the active medium is a Yttrium Aluminum Garnet (YAG) bar containing neodymium ions.

Understanding Gain

The factor by which the light intensity increases in the active medium is known as gain.

The gain is not constant for a particular type of medium; it depends on:

• The wavelength of light.
• The length of the active medium.
• The extent to which the active

Electric field:
- The electric field is the model that describes the interaction between bodies and systems with electrical properties of nature. Mathematically it is described as a vector field in which an electric charge value point "q" would suffer from a mechanical force "F"
- Lines of force:
- There are lines perpendicular to the body surface, so that its tangent at a point coincides with the field direction at that point.
-A greater concentration of lines, most module. In the example of the coin, the field is higher in the vicinity of this and decreases as we move away from it.
- Linking the points where the electric field is equal, we are equipotentials (see Electric potential), points where the potential has the same numerical...

1. SONAR (Sound Navigation and Ranging)

SONAR is a system used to determine the presence of submerged submarines or enemy aircraft. It utilizes the properties of ultrasonic waves to identify the depth of the sea and detect obstacles.

• Mechanism: The SONAR transmitter emits ultrasonic rays in various directions. When these rays strike an obstacle, they reflect back to the receiver. By measuring the distance and time of the transmitted and reflected waves, the velocity of the ultrasonic wave is calculated.
• Mathematical Calculation: If the distance traveled by the transmitted and reflected wave is AC + BC, and velocity v = (AC + BC) / t, then v = 2CO / t. Therefore, the depth of the sea is CO = vt / 2.

2. Piezoelectric Method

Piezoelectric Effect

When...

SRML Half-Yearly Examination - 2080

Class: 9 | Subject: Science and Technology | Full Marks: 50 | Time: 2 Hours

Answer all questions.

Group - A: Multiple Choice Questions (8x1 = 8)

• a. What is the multiplier of the prefix 'micro'? (a) 10⁻⁶ (b) 10⁻⁹ (c) 10⁶ (d) 10⁻³
• b. What is the stalk of a mushroom called? (a) Pileus (b) Gills (c) Stipe (d) Hyphae
• c. Who was the proponent of the theory of natural selection? (a) Hugo de Vries (b) Charles Darwin (c) Lamarck (d) Gregor Johann Mendel
• d. If a load of 400 N is moved using an effort of 50 N, what is the Mechanical Advantage (MA)? (a) 8 (b) 50 (c) 400 (d) 100
• e. Which is not a source of non-renewable energy? (a) Coal (b) Biogas (c) Kerosene (d) Petrol
• f. Which is an example of a longitudinal wave?

Fundamentals of Topography

Definition of Topography

Set of methods and tools necessary to represent the ground with all its natural and artificial details.

Topographic Survey

Set of methods, measurements, and representation of any part of the earth's surface at a given level in the form of a plan or map. This part of the survey is called planimetric survey (X, y). Since the surface of the earth is three-dimensional, topographic survey also includes leveling, which is to determine the gaps between the various points of the surface represented in the plane.

Layout

Operations needed to correctly place any field project and control it during the construction process.

Units Used in Topography

• Length: Meter
• Surface: m² or Ha (10,000 m²)
• Angle: Grads

Geodesy

Bernoulli's Equation and Energy Balance

Since the fluid is incompressible, A₁Δx₁ = A₂Δx₂ = ΔV.

Work–Energy Principle Derivation

The work done on the fluid is due to the pressure acting on it.

Therefore, the work done, ΔW = F₁Δx₁ - F₂Δx₂

= P₁A₁Δx₁ - P₂A₂Δx₂

= P₁ΔV - P₂ΔV

ΔW = (P₁ - P₂) ΔV

Change in kinetic energy, ΔKE = KE₂ - KE₁

= &frac12 mv₂² - &frac12 mv₁²

ΔKE = &frac12 m (v₂² - v₁²)

= &frac12 ρ ΔV (v₂² - v₁²)

Change in potential energy, ΔPE = PE₂ - PE₁

= m g h₂ - m g h₁ = m g (h₂ - h₁)

Since m = ρ ΔV, ΔPE = ρ ΔV g (h₂ - h₁)

Using the work–energy principle,

ΔW = ΔKE + ΔPE

(P₁ - P₂) ΔV = &frac12 ρ ΔV (v₂² - v₁²) + ρ ΔV g (h₂ - h₁)

Therefore, P₁ - P₂ = &frac12 ρ (v₂² - v₁²) + ρ g (h₂ - h₁)

Rearranging