Notes, summaries, assignments, exams, and problems for Physics

Essential Physics Definitions

Electricity and Circuits

• Grounding: Removing an excess charge by connecting an object to Earth.
• Lightning: The discharge of negative electrons at the bottom of thunderclouds to Earth's surface through ionized air.
• Electric Field: The area around an electric charge in which it shows its effect (attraction or repulsion).
• Positive Charge: Lines coming out from the charge.
• Negative Charge: Lines going into the charge.
• Electric Current: The flow of charged particles.
• Electric Power (Watts): The rate at which electric energy is transformed (e.g., a hair dryer).
• Power: The rate at which energy is transformed.
• Voltage: A source of potential difference that is less than the potential difference across the load (or battery terminals)

Ambient: simulate global lighting,  constant in all surfaces. Objects not lighted by extrnl source of light. Lghts parts that cannot be reached by source of light, but seen by  observer I = Ia*Ka

Diffuse: after a source of light incides in a surface, the reflected rays are dispersed in many directions (common: rough surfaces).A surface is an ideal diffuse reflector (Lambert reflector) if it reflects light in all directions with the = intensity → surface equally shiny from any perspective. I =Ip*Kp*(N*L)

Specular: effect of "bright spots" that see in a surface reflecting light, can only be observed from certain directions (common glossy surfaces) ▪ direction of specular reflection  determined by the angle of reflection (𝜙) with respect... Continue reading "3D Graphics Illumination and Surface Shading Techniques" »

newton’s laws of motion 1st when Net force acting on an object is zero, objects will not motion 2nd acceleration of an objects is equal to the net force acting On that object divided by the object mass 3rd when An object applies a force on the second object, the second object applies an Equal and opposite force to the first object in different object indifferent Direction.

Work: when a force is Apply on an object and it moves over a certain distance.

Friction: force that Resist motion of an object is called friction

The law of conservation of energy: it states that energy can neither be created nor Destroyed but can be transform one form to another

Distinguish between kinetic and potential energy: kinetic energy is the energy due to motion of... Continue reading "Coh3 chemical name" »

Static electricity:

• There are electrostatic forces between particles or objects with a positive or a negative charge.
• Charge is due to the surplus or defect of electrons.
• Like charges repel each other while opposite charges attract each other.
• Electric charge is measured in coulomb (C) and has the symbol Q.
• When there is an imbalance of positive and negative charge, we get a force between the charges according to Coulomb's law.

Electric current:

• Electric current is a flow of electrons or other charges through a material.
• Conductor: Electrons can move easily through the conductor.
• Insulator: It is very difficult for electrons to move through the material. The electrons are not free to move and form bonds.

Electrical Magnitudes:

• Potential difference is

Key Figures in Astronomical and Physical Science

Aristotle

• Proved that the Earth is spherical.
• Believed that the Earth was at the center of the universe.

Aristarchus

• He was the first to state that the Sun, and not the Earth, was the center of our universe.
• Used simple geometry to estimate the size of the Sun and Moon and their relative distances.

Ptolemy

• Made a model called the Ptolemaic system, concluding all astronomical objects move at constant speeds in circular orbits.
• Ptolemy built his model to fit this idea. The Ptolemaic model is one of the longest upheld scientific theories in history; it was the cornerstone of astronomy for 1,500 years.

Copernicus

• Concluded that the Sun was the center of the universe instead of the Earth.
• Promoted the concept

Arguments Against Earth's Rotation

1. Centrifugal Force and Stability

The Earth should have broken apart long ago due to centrifugal forces; since this does not happen, the Earth must be stationary.

2. The Problem of Falling Objects

If the Earth moved, falling objects would not strike the surface directly beneath their starting point because the surface would shift during the fall. Since objects fall in a straight line, the Earth cannot be moving.

3. Aerial Motion and Birds

If the Earth rotated, flying creatures like birds, which do not maintain constant contact with the surface, would be left behind. Since this is not observed, the Earth must be at rest.

4. Celestial Spheres and Natural Motion

Some argue that celestial bodies move independently within... Continue reading "Historical Arguments Against Earth's Rotation" »

The Meter Bridge

The Meter Bridge consists of a wire of length 1 m and of uniform cross-sectional area stretched taut and clamped between two thick metallic strips bent at right angles, as shown. The metallic strip has two gaps across which resistors can be connected. The end points where the wire is clamped are connected to a cell through a key. One end of a galvanometer is connected to the metallic strip midway between the two gaps. The other end of the galvanometer is connected to a 'jockey'. The jockey is essentially a metallic rod whose one end has a knife-edge which can slide over the wire to make an electrical connection.

The Potentiometer

The Potentiometer is a versatile instrument. It is basically a long piece of uniform wire, sometimes... Continue reading "Principles of Meter Bridge and Ampere's Circuital Law" »

Reflection of Light

Reflection is one of the unique properties of light. It is the reflection of light, which enables us to see any object.

Reflection: The bouncing back of rays of light from a polished and shiny surface is called reflection or reflection of light.

Laws of Reflection of light: The angle of incidence and angle of reflection is equal. The incident ray, reflected ray and normal to the point of reflection lie in the same plane.

The angle of incidence is denoted by 'i' and angle of reflection is denoted by 'r'. The law of reflection is applicable to all types of reflecting surface.

Mirror and Reflection of Light: Mirror is a shiny polished object (glass) which reflects most of the rays of light falling upon it. One side of mirror is... Continue reading "Understanding Reflection, Refraction, and Spherical Lenses" »

Sign Convention for Reflection by Spherical Mirrors

1. The object is always placed on the left of the mirror.
2. All distances parallel to the principal axis are measured from the pole of the mirror.
3. Distances measured perpendicular to and above the principal axis are taken as positive.
4. Distances measured perpendicular to and below the principal axis are taken as negative.
5. The focal length of a concave mirror is negative.

Image Formation by a Concave Lens

1. If the object is at infinity, the image is formed at the focus of the lens on the same side of the lens as the object. It is virtual, erect, and highly diminished.
2. If the object is at any finite distance from the lens, the image is formed on the same side of the lens as the object and between the focus